Arnova 10 4gb - Good for Watching Video?

[Lorsk]

This appears to be the cheapest tablet with a 10 inch screen, or the cheapest I could find. Please correct me if I'm wrong. It's going for around $160 at the moment and I'm thinking about buying.

It seems to have received a lot of critical reviews, but I would have expected some of that for it costing so little. However, a lot of that criticism doesn't matter to me as the ONLY thing I need it for is playing video files from my computer that I put onto it via the micro SD slot or USB. I just want to use it to watch shows while I'm on an elliptical machine at the gym. So I'm wondering for those of you who have used one:

-How is it at playing 720p video? Does it stutter or look bad in some way?
-Can video files be played directly off an SD card or USB drive that is plugged into it?
-Even though it says it can play basically any video format, have you ever run into anything being incompatible?
-What about subtitles?
-I was also wondering if you can use bluetooth headphones with it such as the Motorokr S305.

If anyone can answer any of those questions, I would really appreciate it.