Garmin has much more sales, more users, and way more SKU’s- of course they have more issues. Software (especially that interacts with smartphones and laptops ever changing software) is hard. This is why most new power meters flame out badly. The hardware is easy- the software, firmware and customer service is the hard stuff.
I have has issues with various Garmin products, generally a spot of googling sort things out. Although I have seen the same open water issues DCR saw. Generally, the Garmin ecosystem works pretty good.
On Wahoo- go see the specific Facebook page for them, it is a frickin’ horror show. Especially the newest Kickr and Snaps (DCR detailed this earlier this year). I have a first gen Kickr and was looking to update, but no-- just no.
Polar- lol, is it 1996? Polar had the market at one time, and basically lost it all with endless jank, no innovation, a truly awful PM and high prices.
Frankly there are a lot of head units out there- but how many will be supported at all in 2 years?