I've been walking around Dealer's Den and I noticed that there's a sizeable amount of AliExpress items but then I thought that presentation is part of the service. I mean sure, it's bad if it's all AliExpress, but if it's just a bit then it's not exactly a problem, because the merchant is doing the work of discovering interesting items and then presenting them nicely. I bought a few things that I could as well order on Amazon but I never did because I didn't know it's actually that nice.
In a healthy community people will notice crap and simply won't buy it, which discourages merchants from selling crap. If that's not the case, then it's quite likely that the community has bigger issues because they cannot distinguish crap from good items.
I mean, if someone shows up with hand-made crap then the community should also push it out, whether it's hand-made or mass-produced is pretty much besides the point.
Regarding the cons themselves, of course there are good ones and bad ones. That's how it is with everything.