Big complaints: lack of consistency, fonts sized for use on monitor not TV, cheap taiwan-style file browser elements that look like they were lifted from a generic $50 media streamer. I also really hate photos used to show what menu item you have selected (for instance the giant picture of the living room and TV)

SageTV copied the UI for version 7, except with very bad font choices, crappy photos and poorly drawn graphic elements. Needless to say, I'm still using the UI from version 6.

No one gets it 100% right, but the parts Boxee got right, IMO, work a lot better than most others.

I do still wish that more people would learn from TiVo's really simple left and right (in and out / forward and back) method of entering and exiting menus. All this having to press a menu key which actually means "back" (copying Apple's lame iPod UI) is really annoying (Boxee does this).