I will never trust them, any more than a used car salesman. LOL
My Sigma wired ones are 99.8 % accurate 99.8% of the time. I roll the bike by a measuring tape and then add a few mm for wiggling and loading. I'll take accuracy and ease of use over pretty, every time. I also use the temperature reading in my apartment all the time. I'm pretty sure it is 99.5% accurate for that as well.