The dealbreaker for me is actually the GUI and the inability to FF/RW without a preview. If you want to find a specific scene in the video it takes ages. We gave it a whirl for about three months to get used to the interface, but I eventually decided that I can’t get used to it. Apple did such a fine job in spite of not being 100% what I’d like to have.
And yes, I’m only having this lagging video issue in boxee … loading the ad supported files … not the local ones. I’ve seen them stream on a boxee box just fine though.
So in our case, we have reverted to iTunes and syncing (which is fine to take those extra steps), and it keeps the libraries identical with all three of our ATVs (in terms of what you have watched or not-watched). My efforts currently are on finding other ways to stream, that will work on both an ATV1 and ATV2. Looks like Playon might be a good way to go. Only down side, is we are mostly macs here, and Playon is only available for PC. Perhaps an old dusty PC from the closet might do the trick. They recommend that ONE of the sources be cabled (either the ATV or the PC). If they’re both wireless they hinted at bad results.
Plex on the ATV2 is sweet … but honestly not sweet enough. But at least their interface is very slick and nice.
My position today … is serve the local media from iTunes, and then use the other apps to add more features and flexibility.