Amazfit Cheetah 2 Ultra vs Fitbit Air: GPS Watch vs Health Tracker

Overview

These two devices are not really competing for the same buyer. The Amazfit Cheetah 2 Ultra is a serious GPS running watch aimed at performance athletes who want dual-frequency tracking, muscle oxygen monitoring, and trail-grade capability at £599.90. The Fitbit Air is a compact health tracker pebble aimed at health-conscious users who want continuous monitoring without a full smartwatch. Comparing them directly is useful only if you are deciding whether to spend serious money on a running watch or stay in the tracker category.

Specs at a glance

Price: Amazfit Cheetah 2 Ultra £599.90 vs Fitbit Air mid-to-upper-mid tier (exact price unconfirmed)
GPS: Cheetah 2 Ultra has dual-frequency GNSS; Fitbit Air has no confirmed GPS chipset
Battery in GPS mode: Cheetah 2 Ultra 55 hours projected; Fitbit Air not confirmed
Heart rate sensor: Both use wrist-based PPG optical sensors measuring blood volume changes via LED light
SpO2: Both include optical blood oxygen saturation
Muscle oxygen (SmO2): Cheetah 2 Ultra yes; Fitbit Air no
Barometric altimeter: Cheetah 2 Ultra yes; Fitbit Air not confirmed
Form factor: Cheetah 2 Ultra is a full watch; Fitbit Air is a minimal display pebble

GPS and tracking accuracy

The Cheetah 2 Ultra scores 81% on a standardised 10-mile GPS accuracy test, rising to 85% across broader trail testing. That is a real improvement over the Cheetah 2 Pro's 73%, and dual-frequency GNSS is doing meaningful work here. The Forerunner 970 still beats it at this price point, but the Cheetah 2 Ultra is competitive for trail running in patchy signal conditions.

The Fitbit Air has no confirmed GPS chipset. For any distance or route tracking, it would depend on a paired phone or simply not offer it. If GPS accuracy matters to you at all, this comparison ends here.

Battery life

The Cheetah 2 Ultra projects 55 hours in GPS mode. For a runner doing ultras, long trail days, or back-to-back training blocks, that is a practical number. Real-world use will vary, but 55 hours gives meaningful headroom.

The Fitbit Air has no confirmed battery figure available. Given its pebble form factor and always-on health monitoring focus, it likely prioritises multi-day passive tracking over GPS endurance, but no concrete hours can be reported here.

For athletes: who wins?

Road running: Cheetah 2 Ultra. 81% GPS accuracy, strong optical heart rate performance across multiple tests, and structured training metrics make it the clear pick.
Trail running: Cheetah 2 Ultra. 85% GPS accuracy in technical terrain, SmO2 muscle oxygen monitoring, and barometric altimeter give it real advantages off-road.
Triathlon or multisport: Cheetah 2 Ultra. The Fitbit Air has no confirmed GPS, no multisport mode, and is not built for this.
Recovery and daily health monitoring: Fitbit Air has a case here. In controlled gym and steady running conditions it matched devices like the WHOOP MG to within one beat per minute. However, testing also showed it produced the widest error range of any device in at least one HYROX simulation with full statistical analysis. That inconsistency is a problem for anyone relying on recovery data to make training decisions.

Verdict

The Amazfit Cheetah 2 Ultra is the obvious choice for any runner or athlete. It has GPS, meaningful accuracy improvements over its predecessor, a 55-hour GPS battery, and performance sensors the Fitbit Air simply does not carry. The Fitbit Air is not a running watch and should not be evaluated as one. Buy the Cheetah 2 Ultra if you train seriously and want a capable, data-rich watch that is cheaper than Garmin's equivalent, accepting that Garmin still edges it on raw GPS precision. Buy the Fitbit Air only if you want passive health tracking in a minimal form factor and can accept inconsistent accuracy in higher-intensity workouts.