I hope this thread doesn't delve into just a bunch of attention whores claiming to know stuff but not actually divulging any information lol
I've never been to one in Flushing cause I don't speak Chinese and don't know even where to start, but I have spoke with girls that have worked at these places and I think these girls are basically your standard run-of-the-mill 10-day girls.
Meaning, they are usually going to have the more asian look that chinese guys prefer - Fair-skinned, Black/dark hair, etc.
I think the main advantage to these places is the fact they rotate girls so much so you'll always have variety, and if you prefer white skinned dolls versus tanned busty models at KMPs. And of course price, but it's basically one shot and you're out, so don't expect too much service.
Age wise, I don't think it's significantly different... Sometimes you'll find someone in their 20's, but mostly 30's, and even 40's
Also it's been my experience that at 10-day Chinese houses I've been to outside of Flushing, Chinese girls are most apt to give BB services if that's your cup of tea. I've met plenty of Chinese girls who will give up BBFS for just $100 and BBBJ for $40. You can find Chinese houses for $120, $140, $160, so basically you can usually get BBBJ servie for $160-$200.
If the reason you want to try these Flushing houses is because you think you'll find younger or hotter Korean girls... I don't think you'll find it aside from the appearnce-preferences I mentioned above.