The trackball on mine works great and is very responsive. It's nice having hardware buttons on the side.
The trackball works well but it works pretty much like any other trackball on other android devices i have used, meaning that it never scrolls enough with one swipe, which is fine if you want to scroll down a screen slowly, not so great when needing to scroll down a long webpage fast.
My unit came with Google Maps and Market pre loaded. It also had a few games pre loaded including fruit slice and angry birds.
Lucky you, ours don't have either, what firmware version does yours have?
I dropped some 720p mkv files on and they ran perfectly and look nice on the high res screen.
Thanks for that feedback, i haven't tried videos yet, do you have any 1080p vids you can try?