The new 'nudge' controls, seen below, rewind a playing video by 7 seconds and advance a video by 30 seconds, though there's no way to adjust these values if needed. This control is, of course, in addition to being able to simply drag the playback marker on the timeline:
I also noticed more reliable resumption of playback in commercially bought/DRM-ed video content. Commercial downloads also pop-up an 'i' (for 'Info') icon in the toolbar - tapping this goes back to the 'home' page for that content.
Great to see continued updates to both Video and Music (which also got an update, yesterday, though nothing new of significance in the UI).
You can grab or update Xbox Video here in the Store. Comments welcome on reliability now - how does it work for your own bought content?