I can't speak for garmin but Wahoo have outstanding customer service. I've had three issues, two with a kickr during the infamous Vietnam handover and once with a Tickr, each time they replaced the products with brand new ones without hesitation or any back and forth, two of which were technicaly outside of warranty.

And for this reason I will continue to buy Wahoo products. I HATE when you have to get aggressive with companies to get them to do the right thing by their customers, when you have a company that shows they actually care and replace items without the normal back and forth agro it makes a HUGE difference.