This unknown and shady Quickex can't be compared with eXch. While eXch is highly recommended, Quickex should be highly avoided. The mere fact that the latter requires KYC means they're total opposites.
Of course, they are not the same. I don't compare them, I say that I've used both and I haven't had any kind of problems so far.
You mentioned about checking of address to guarantee 100% exchange without blocking. As far as user complaints are concerned, they're locking funds. They'll freeze coinjoined and mixed funds. Moreover, subscribing to the idea of clean and dirty coins is a big no for many Bitcoin users.
I am aware of this information. As I said, they probably have to comply with the requirements of their liquidity provider. I get a 100% guarantee that my exchange will not be stopped from them and receive clean crypto after the exchange is completed, that is all that matters to me. If I got it right from reading their topic, they locked funds only with high risk percentage (for example, they won't accept stolen coins). I guess this is made to prevent situations like the one that has happened to eXch, they don't want their business to be shut down.
On top of all this, I guess BestChange even kicked them out. Trustpilot also made their reviews unavailable once for guideline violations.
I don't trust Bestchange too much. There have been cases when the swapping services listed on Bestchange have scammed their customers. Apparently, there were reasons to remove Quickex from the listing. Probably it was because they got too much negative reviews or something. I don't want to defend Quickex, I just say that my experience with this service wasn't bad.