I've used before. I bought the A320 Dingoo with them. They are not bad. And very willing to deal with e-mail. As I understand, they are new and I think that they are working to get the entire site running.
As a new Dingoo owner myself, I was trying to load all the file types that the Wikipedia article said it would run....
No luck with mp4s or MOVs... I'm guessing it's the H.264 codec. Any fixes?