HI Kalle-
I actually have some of these Revolabs mics at my job and I've never been too fond of them, mostly because of the stupid wired-in li-poly packs in the mics, which tend to bubble and are not easily replaceable. They're expensive, but not crazy expensive if you're hell-bent having some. You can get a pair with a charger and receiver for about $500...
For my purposes, though, I need something that's commodity priced.
I'm sure the Pyle mics are crap-tacular, and there's essentially no QC, as one would expect at this price. I expect I'd have about even odds of getting a set that works, so I'd be operating in the land of calculated risk if I went ahead. But the idea for the product is conceptually almost exactly what I want, and it's the only thing I've ever seen at almost any price that ticks all the boxes (except quality). I am afraid! But if they work it would be a cool proof of concept.
Anyway, there are still plenty of things that need done before I haul off and buy a bunch of mics. I'm just really interested in multi-room strategies since my home, small though it is, has multiple rooms...