Just completed it now, after getting it for Christmas. It was certainly better than the first one, and quite good fun.
Had to get a bit of help for a few (3 or 4) of the later levels, but I'm pleased to say that was all the help needed!
I thought Ricky Gervais did the voice of Wheatley, but apparenly not.
It was interesting to see the progress of computers as you went through the second half of the game - from 1958 to 1980, you see computers change from mainframes to desktop machines, along with pictures of Cave Johnson as he gets older - who ends up one fish short of an aquarium...