I saw a lot of those chinese suppliers at the Light and Building Fair in Frankfurt.
The quality differed enormously between suppliers, esp with the diffuser they used (can you see the leds shine through or is it a nice even lighting).
There were very good ones and bad ones, so how do you notice it when you buy on Ebay: you can't
What is stopping you from building them yourselves with quality A leds and driver?
I was at the same show and had the same experience
Basically quality varies wildly between suppliers, some customers/importers are in a race to the bottom in terms of cost so some of the China factories will use lower quality LEDs and less of them. The dangerous part is when they skimp on the driver, I've seen some awful drivers for these really basic "wun hung low" clearance and isolation errors and the associated build quality.
On the other hand there are some of these China suppliers that are up to scratch, TUV approvals, good drivers and lm/w figures that match the specifications, you just really have to do your homework on them all. We did a tear down of one China companies drivers and it was an example of good engineering, it was plastic welded so they never expected it to be seen, even so it was full of all the right stuff, genuine Rubycon caps, well insulated transformers. Even so I'd do a regular check on batches, sometimes when haggle down a price with a China supplier they were already at rock bottom so that 10% discount you get means they go and try to make the savings by reducing specification.
I'd steer clear of ebay/aliexpress China suppliers, frankly it's impossible to air ship a good quality LED panel and keep the cost competitive, a corner will be cut somewhere.
So can you rely on your local wholesaler to bring in good gear? Sometime yes sometimes no, it varies wildly and comes down to whether they care about quality or just bring in the cheapest they can find. They are probably your best bet as you can have a look at them first and take them back if they are not up to scratch.