What exactly makes a great smartwatch? Is it size? Is design? Is it features? Is it cellular connectivity?

The answer's going to be very different for everyone. While Apple thinks cellular is the key to transforming the Apple Watch from good to great, Samsung's betting big on fitness tracking with its latest smartwatch, the Gear Sport.

But is it better than an Apple Watch? And does it even matter?

Priced at $299.99, Samsung's Gear Sport slots in-between the Gear S2 Sport/Classic and Gear S3 Classic/Frontier. That's less than an Apple Watch Series 3 without cellular connectivity, which costs $329.

But don't let the $30 difference deceive you. Buying a smartwatch is trickier than it looks and ultimately depends on what kind of phone you own. It's a lousy reality, but it's true: Smartwatches are designed to work better with certain smartphones.

It really comes down to this: If you're using an iPhone, get an Apple Watch. If you're using Android, you're looking for an Android Wear smartwatch. And if you're using Samsung -- well, Android Wear will work just fine, but Samsung's own Gear smartwatches work better.

Of course, Android Wear does work with iOS. But it's really crappy. Like horribly crappy. And Samsung's Gear smartwatches also work with iOS, but like Android Wear, you're getting a gimped wearable experience because Apple doesn't let you do things like compose text messages or reply to received ones.

But if you're less concerned about the smartwatch features and robust fitness-tracking features are a top priority, the Gear Sport's worth considering even if you don't use a Samsung phone.

Just the right size

Having tried dozens of smartwatches over the years, I've come to realization that there is no perfect size for smartwatches. I can only comment on what feels right for me.

For me, 42mm seems to be the most adequate size for the watch case. Any smaller and the smartwatch's screen is too small and any larger and I feel like the whole thing's weighing my wrist down.

So I'm really glad the Gear Sport comes with a 42mm case with a 1.2-inch round Super AMOLED display that's sharp and easy to read in all situations. At first the Sport seemed a tad thick at 11.6mm, but it's only a hair thicker than the 11.4mm Apple Watch Series 3.

While extremely bulky watches are a concern (though, I'm a hypocrite because I sometimes wear a Casio G-Shock), comfort is arguably more important. Whereas I've never worn my Apple Watch to sleep, I didn't mind going to bed with the Sport on. The always-on screen displayed the clock at all times and not in any blinding way.

Samsung used to be known for some really ugly designs, but the Sport is among its best. It's light, stylish (it comes in a polished black or navy blue), and works with any 20mm strap. Included in the box is a large and small silicone band, but I hate these rubbery straps, so I swapped in a neon orange band from an old Timex and a leather one from a Moto 360, and they look great.

And if you've ever used a Gear S2 or S3, you'll know just how satisfying controlling Tizen OS with the rotatable bezel is. Rotating it clockwise from the watch face opens up the various widgets you've set up (by default, they're set to fitness-tracking that show stats like calories burned, steps, floors-climbed, heart rate, weather, etc.).

There are two buttons on the Sport: back (top) and home/power (bottom). Pressing the latter opens up a beautiful circular ring of apps that you can then browse through either with a swipe or by rotating the bezel. Using the bezel control is fast, logical, and the best interface on a round smartwatch I've ever seen, and makes a mockery of Android Wear.

Fitness-charged

Companies are learning the hard way that there are only really two things people use their smartwatches for: notifications and fitness-tracking. Everything else is just extra.

In the two years I owned an Apple Watch, I never once loaded a single song onto it. I couldn't even tell you how to do it. Tech companies talked a big game on how apps on smartwatches would be just like they were on smartphones. But it turns out apps on smartwatches really suck for a number of reasons: the screen's too small, the input is too limited, and wrist-worn wearables are a more quick-glance type of device instead of something we interact with for extended periods of time.

If you've used a Gear S2 or S3, you'll know just how notifications work. They come in and you can either interact with them immediately or swipe right from the watch face later to see them. It's all pretty standard.

The Sport is a fine smartwatch on its own, but where it really earns its name is fitness-tracking. Samsung's added a ton of features that makes it practically pointless to own a Fitbit or general-purpose fitness tracker.

The smartwatch comes with all of the usual step, floor, running, and biking tracking you'd expect from a fitness wearable, and a few new ones that take things to the next level. It's about as accurate as an Apple Watch, give or take a few hundred steps (there's always a slight variation between fitness trackers).

There's a built-in GPS for more accurate location-tracking. It's super handy for when you don't want to bring your phone with you on a run, but still want to get live maps on the Sport. I used it with Under Armor's Endomondo and it just worked.

Samsung's also beefed up the heart rate sensor so that it works continuously throughout the day. It's good to have this, but I found the sensor a little slow to read my heart-rate. Not sure if that's something that can be sped up with a software update or not, though.

The Gear Sport's also rated for 5-ATM water-resistance, which means it can be worn safely in a pool and the ocean, and can be submerged in depths of up to 164 feet (50 meters).

In addition to automatic activity tracking for more exercises like rowing, jumping jacks, lunges, and crunches (to name a few) there's a new feature that lets you track your food calorie intake. It's a nice little addition, but you have to manually add all your food, which can get a little tedious if you're really uptight about it.

And if you aren't convinced this the Sport packs enough fitness-first features, you may care to know that there's tighter integration with third-party fitness apps like Under Armour's suite (UA Record, MapMyRun, MyFitnessPal, Endomondo).

Samsung's also partnered up with Speedo for the Speed On app, which is supposed to offer some of the best swim-tracking features around (unfortunately, this app wasn't live during my review period, so I'll have to update it once it is).

There are a few other cool fitness features like a digital guide that'll walk you through various cardio workouts either on your phone or a supported Samsung TV. This is yet another feature that wasn't available while I was reviewing the Gear Sport, but I saw it in action a few months ago at IFA and it seems pretty neat.

It's probably not going to replace a real coach, but looked like it would push sloths like me who need a good external motivator (even if it's a virtual one) to do anything fitness-related.

Samsung's finest smartwatch yet

Making a smartwatch is extremely challenging, especially when it's one that aims to please as many people as possible.

That's one of the things that the Apple Watch does well. It does notifications really well and it's been piling on the fitness features since last year as the company's honed in on what the device's users are actually using it for.

I believe Samsung's on the same trajectory with the Gear Sport. It's a handsome smartwatch that's just the right size, nails all of the basics of a smartwatch, and comes with a slew of fitness features that fitness nuts (the non-professional, non-Olympic kind) will love.

If there's any one weakness that the Sport suffers from, it's weak battery life. Samsung says the smartwatch's 300mAh battery lasts up to three days. I'm not sure how it measured that, but I barely made it through a day, and I noticed battery draining faster (most likely because of the GPS) than on an Apple Watch. Expect to plop this guy on the charger every night or it'll be dead before you can get any real fitness tracking in.

A day of battery isn't a deal-breaker, though. However, not having cellular connectivity, might be. The Apple Watch Series 3 is impressive not because it finally has LTE (Samsung's Gear S3 had it a year ago), but because Apple added cellular without making the case larger.

True, adding cellular on the Apple Watch costs an extra $70 over the regular Bluetooth model, or $100 over the Gear Sport, but it's hard to deny that the size and feature hit the sweet spot for a lot of people.

Samsung gets so much right with the Gear Sport -- I think it's the company's best smartwatch to date -- but Apple's just flipped the table again with the Series 3 and cellular.

If this isn't a feature you care about -- it blows that carriers are forcing you to pay a small monthly fee to basically access data for your smartwatch from your regular data plan that you're already paying for -- the Sport is the best alternative available, and a much better value than the disappointing Fitbit Ionic smartwatch.

Samsung Gear Sport

The Good

• Super comfy

• Bright, sharp display

• Top-notch fitness-tracking features

• Handy built-in GPS

• Easily swappable bands

The Bad

• Weak battery life with GPS turned on

• No cellular connectivity

The Bottom Line

Samsung's Gear Sport is its finest smartwatch yet, even without cellular connectivity.