Lastly, I appreciate that the watch automatically detects workouts after a certain period of time. I use this feature daily as I walk to and from the subway and around my neighborhood. After 10 minutes, the familiar vibrating tick, with a message asking if I want to record an outdoor walk. The answer is always yes, and the watch thankfully includes the previous 10 minutes in which I forgot to initiate a workout.

But what of running? In short, you’re getting the basics and not much else. You can see your distance, calorie burn, heart rate, average pace and also rolling pace, which is your pace over the past mile at any given moment. You can also set pace alerts — a warning that you’re going faster than you meant to, for example. Given that this is an Apple Watch, you can also stream music or podcasts, if you have the cellular-enabled LTE model.

Because the watch has a GPS sensor, you can leave your phone at home while running — which wasn’t an option in earlier versions. Of course, no two brands of running watches will offer exactly the same distance readout on a run; indeed, my friends’ watches and mine often disagree, even if we ran the same route side by side from start to finish. That said, my anecdotal experience is that the Apple Watch often says I ran farther than other watches would, which means my average pace is also faster than I’d expect. That last metric is the real red flag: You can convince me I ran a fifth of a mile farther than I think I did, but after a point, it’s hard for me to believe I ran as fast as Apple claims. I know my limits.

On a brighter note, the Apple watch integrates with some treadmills and other exercise equipment, thanks to a two-way pairing process that essentially trades notes between the device and gym gear, formulating a more accurate estimate of your distance and effort using that shared data. The technology, called GymKit, is compatible with equipment made by Life Fitness, Matrix Fitness, TechnoGym, Cybex, SCIFIT, StairMaster, Star Trac, Schwinn and Nautilus. Support for Woodway, True Fitness and Octane Fitness is coming soon as well.

In my experience, the watch usually agrees with the treadmill on how far I ran, which is not always the case with other wearables. As such, though I sometimes suspect the Apple Watch is overstating my distance on outdoor runs, I have more confidence in its ability to accurately track treadmill workouts.

Regardless of whether you run indoors or out, all of your stats are listed on a series of pages, which you swipe through from left to right. In my early days with the Series 4 it was tempting to use the Digital Crown as a stopwatch button, similar to how I use every other running watch. This urge has mostly subsided as I’ve gotten more comfortable with the user interface. Like many of its competitors, the Series 4 has an auto-pause option, which I use often in start-and-stop workouts.

All told, this is a fairly limited list of stats, without much room for customization. There’s no mode for interval workouts, either by time or distance. There’s not much of an attempt to quantify your level of fitness, your progress or the strenuousness of your workouts or training load. None of this will be a dealbreaker for more casual runners. Ditto for the distance tracking; it sometimes seems slightly off to me, but it might well be good enough for someone just trying to get credit for their runs.

For more detailed tracking, your best bet is to experiment with third-party running apps for the iPhone, like Strava, RunKeeper, MapMyRun, Nike Run Club and others. It’s through trial and error that I finally found an app with Watch support and timed intervals. But at the end of the day, it’s easier to wear a purpose-built running watch when I’m running outdoors, sync my data to Apple Health, get my exercise and standing-time credit, and then put the Apple Watch back on the first chance I get. But if you can only afford one smartwatch for training and life, there’s a strong case for choosing this one.

Garmin Forerunner 645 Music

For many of the marathoners I know, Garmin is the gold standard in running watches: Its devices are feature-rich, easy to use and offer long battery life. I’ve been living with the company’s Forerunner 645 Music watch for about a year now. It’s the highest-end model in Garmin’s running lineup, and as the name suggests, it features onboard music storage (“up to 500 songs,” says Garmin), among other niceties. It’s worth noting up front that if $450 feels like a lot to spend on a running watch (or if music streaming seems unnecessary) Garmin offers cheaper devices like the 245 that share much of the same DNA.

Though the 645 Music has the word “runner” in its name, I should clarify that this is actually another multisport watch, with the ability to track swimming, cycling, weight reps and more. Like many of its competitors, it lets you customize the onscreen data pages and has features like auto pause, auto lap, manual lap, heart-rate zones and alerts, and configurable intervals based on time or distance. As a fitness tracker, it tallies steps taken, calories burned, floors climbed, intensity minutes, sleep and one’s overall stress level.

Things get more advanced as Garmin attempts to rate both your level of fitness and the effectiveness of your training. The watch calculates your VO2 Max — an indicator of both endurance and cardiorespiratory fitness. In tandem, the watch also predicts marathon and half-marathon times, though in my experience (and that of every runner I know) these times are more than a little ambitious. As of this writing, the 645 Music is projecting a 3:45 marathon for me; I’d be delighted just to break my personal best of 4:52. Garmin also uses your VO2 Max to calculate a “fitness age” inside its iOS/Android app, which is more flattering than anything else. At 34, I’m told I have the fitness of an “excellent 20-year-old.” Thanks!