1 - Yes, I was talking about the Pi 2, I got it mixed with the B+, my bad.
2 - I'm not sure when (or even if) I'll deploy it in a classroom: I want to suggest Pi 2 as an alternative to the school board, I don't make the decisions myself.
They are thinking about refurbishing a computer room where all the PCs are dead but the screens are in working condition, so this may be soon (next month? later? never? - again, I don't make the decision).
3 - I don't know about a particular benchmark for Gcompris, I would like to know whether a general purpose usage goes smoothly (no heavy lag or crashes).
I have asked a friend in the US to send me two Pi 2, but I don't know when I'll get them, so if I have to recommand the Pi 2 for the classroom, I may not be able to wait until I can test myself.