I have updated my Apple TV to 4.1.
I’ve not really noticed any different as I haven’t been using it much before I updated.
Having used it a little more recently I have found that it is much faster than Front Row on my Mac mini for moving between media from the iMac downstairs. As a lot of my media is in standard definition the 720p resolution hasn’t been much of a problem. Also all my iTunes HD content is 720p so the fact that it can’t play 1080p content at 1080p is at this time not so much of a problem. I wonder for the future whether this would be a software upgrade or (more likely) Apple will release a new model of the Apple TV.
It’s a pity that BBC iPlayer and other similar services aren’t available on the Apple TV, I personally would like to see 4OD on the Apple TV.
So will we see Apps for the Apple TV in the future, one can hope.