I had a 16 voice REV2 keyboard that had a faulty voice chip.
It was replaced by my retailer and the second was perfect.
There was only 1 digit difference in the serial numbers so I don't think it's a case of there being 'bad batches', just that out of hundreds of synths using analogue circuitry there's always going to be a few that are faulty.
Other minor issues have been remedied by DSI via software updates, which is probably why you're struggling to find as may problems now in your search.
So yes I'd say if you're thinking of a REV2 go for it!
I doubt you'll be disappointed, it's a cracking synth.