This is going to be an 'Indiana Jones 4' of on an album, you're either going to love it or hate it.
Its a great compilation of their best songs, the order is interesting, but any Radiohead fan will already have the majority of these tracks. Its just on one handy CD. For the newbies to Radiohead it's a great listen.
Yes, it's an EMI cash in since the band have left the label. All the classics are on disc one, if you can get hold of the 2 Disc edition (which Amazon are strangely not selling currently) I would recommend that more, as it holds some of the more offbeat tracks and gives you more of a rounded impression of their music.
An alternative though would be to buy the Limited Edition Box Set and get them in all their glory, that's minus 'In Rainbows' mind.
This is getting 5 stars for the music.