Which is the Better Mountain Bike? Please Answer :)?

Rockrider looks pretty good. Contrary to 'popular' belief GT's lower end bikes don't have a good reputation. I would probably try and have a look at low end Specialized if you can. Got a good review recently in a mag (WMB I think). Get down your local bike shop and see what they have too. You'll get better after sales support as well most likely (although I can't guarantee this). Halfords isn't always that bad if you know what you're looking at. Just don't bother taking it back for the free service. I got an (old) GT knocked down from �700 to �300 after I popped in to get some de icer. But that was a stroke of luck.