I tested four top smartwatches through a Spartan race, 12 miles of running, and sleep tracking to determine the best fitness companion. After a week of using all four devices together, the Amazfit T-Rex 3 Pro emerged as the most consistent performer. Each watch was worn simultaneously through sleep, training runs, and an actual race, creating a unique but effective test. My coach raised an eyebrow at the sight of four watches on my wrist, but the results provide real help for anyone shopping for a smartwatch this year. The goal was to find the device that offered the most reliable data for fitness tracking, and the T-Rex 3 Pro proved itself in every category.
Tracking sleep through four devices
The first test involved sleep tracking, which is a core feature for most smartwatches. The Galaxy Watch Ultra 2 collected the most detailed data, including skin temperature measurements tracked against a two-week baseline. However, it also overcounted my sleep interruptions, suggesting I woke up 18 times when in reality I was disturbed only a few. The Amazfit T-Rex 3 Pro, on the other hand, offered sleep data that matched my actual experience. While the Ultra 2 was more detailed, it came at the cost of accuracy in this particular case. My sleep felt disrupted more than normal, and the 54 sleep score from the T-Rex 3 Pro matched that feeling better than the 72 from Samsung.
The Honor Watch 6 provided the least amount of sleep data, offering only percentages and vague categories like 'normal,' 'high,' and 'low.' The interface was not user-friendly, and I found it difficult to dig deeper into the information it provided. The OnePlus Watch 3 43mm offered a better view but missed some key metrics like SpO2 and breathing quality. Each watch had a slightly different approach to sleep tracking, but the T-Rex 3 Pro delivered a balance of detail and accuracy that made it stand out.
Running data shows clear differences
The next test focused on GPS tracking during 12 miles of running. The results varied significantly between the four watches. The OnePlus Watch 3 43mm was the least accurate in terms of path tracking, often misplacing my position on the route. The Honor Watch 6 had issues in areas with tree cover, incorrectly placing me on the road instead of the sidewalk in some sections. The Galaxy Watch Ultra 2 and Amazfit T-Rex 3 Pro performed the best, staying consistent with the actual route I ran. The Ultra 2 even provided more detailed maps, but it did struggle in some areas where the signal was weak.
Beyond GPS, metrics like altitude, cadence, and speed revealed more discrepancies. The Galaxy Watch Ultra 2 completely missed the cadence measurement, while the OnePlus Watch 3 43mm showed erratic speed changes, likely due to GPS inaccuracies. The Honor Watch 6 misread altitude, making it difficult to compare with real elevation data. The Amazfit T-Rex 3 Pro, however, did not show any outlier readings during the 12-mile test, maintaining consistent accuracy across all metrics. This consistency made it the standout device during the running phase.
Spartan race confirms top performer
The final test was the Spartan race, a real-world challenge that put all four watches to the ultimate test. During the race, both the Amazfit T-Rex 3 Pro and Galaxy Watch Ultra 2 performed strongly, but the T-Rex 3 Pro proved to be the most reliable. It consistently delivered accurate data across all metrics without any noticeable errors. The Ultra 2 did well, but it had some instances where the data was overly sensitive to movement, leading to minor inaccuracies. The Honor and OnePlus watches, while decent in other tests, struggled to keep up with the demands of the race. The T-Rex 3 Pro’s overall accuracy and reliability during the race confirmed its position as the best smartwatch for tracking endurance and performance.
