I have a GT Peace 9er and I love it. Mine is a few years old and has V-brakes not discs, but apart from that it looks pretty much the same, and it's a hell of a bike for the money.
Make sure you check how wide the rims are on whatever you get, as mine are 28mm, which would probably be a bit weird with 28mm tyres, and some 29er rims are wider still.