Mine’s absolutely fine. HR / cadence / power only as accurate as the sensors supplying them. Barometric altimeter actually pretty good compared to Garmin (I’m convinced that a Garmin foot is about 30% less than a standard foot).
Stuff that’s not so good? If you use it with Shimano Di2 then you’ll get a global ANT+ reset about once a ride, where you’ll lose all sensor data for about 30 seconds. You can fix this by not pairing the Di2 sensor, though.
In a left turn, there’s a glitch with the top row of LEDs where they don’t work properly. Wahoo admit it’s a bug, but that was six months ago and it’s still not fixed.
Apart from that, it’s leaps ahead of Garmin. Easy to use, easy to read, and battery life is epic. Screen on the normal ELEMNT definitely better, though, bigger and “whiter”.