I give Garmin credit for their customer service call back system and patience in trying to troubleshoot inaccurate readings on my Vector 3 (repeatedly off, compared with a Stages and Wahoo Kickr on the same TrainerRoad workouts). My first Vector 3 had 20-25% +/- readings and they replaced it. The second one, afree perhaps 10 rides and repeated calibrations, would settle into an 8-12% difference, only to give me wildly off readings after battery replacements when the device would reset itself. They refused to honor my concerns about accuracy at that point. Just replaced the Vector with a Favero Assioma—accurate power numbers matching the other two PM’s right out of the box..
Terribly unreliable product for me, waste of $700 and a lot of effort...