Brief overview - DON'T BUY ONE!
I can't speak for the other models in the range, and perhaps the Ainol players with the Samsung screens are much better, but overall I've been hugely disappointed with the player.
I understand that its a Chinese product, so it didn't come with any instructions, fortunately I was able to update the firmware by reading on here. But it was over-complicated. Once this was done and I had calibrated the screen with my NDS pointer I was quite surprised by the average looking screen.
My 5 yr old Archos 504, which broke down and hence why I needed to get a new PMP screens was much clearer and crisper. I found the screen to be quite dull and uninspiring. Even watching a 720p HD version of UP, which has a beautiful palette - I found the colours very drab and the screen and colour was nothing but average.
I know that most people have managed to get SD cards to work on theirs, but having tried 2- neither were working, and I just think that as expandability is a main selling point, this seems very cumbersome and it should be a lot easier.
I also found the sound to be very tinny and weak, again compared to my old Archos 504, which had a bombastic and wide range of sound.
Overall - even for a cheap PMP (but I haven't really found a more expensive one to compare it to) I found it to be all style and no substance.
Other annoying things which I know has been commented on is the subtitles that you can't remove, and also when watching a video, the FF button sometimes skips forward to the next video rather than actually FF.
So in a nutshell, I'm sending it back and have bid on an 80gb Archos 504 on ebay. It was nice to try the so called 'new' tech, but really it wasn't worth it.
I have higher hopes for my MIDnite that's due to arrive, and can only hope it impresses me more than this cheap pile of poo.