Carrera Kraken, prices vary madly but right now it's £380, which makes it very nice indeed. Only shortcut in the spec is the truvativ crankset, everything else is solid enough. I could be wrong but I think the frame is the same as the old Fury (£500 range) though with a little less butting. Nice proven geometry. (I think the old frame was the same as the Mongoose Amasa, oddly enough, just with different cable runs)
A lot of bikes in this price range come with XCR forks… These are actually pretty nice when they work, but you need to stay right on top of the servicing- clean after every ride, strip and clean whenever it seems like a good idea. This isn't a big deal, it takes about as long to strip and clean them as it takes to lube a chain but if you don't do it, the plastic bushings wear and the fork develops a bit of slop, and will judder on compression, not nice. But keep them in good condition and they're better than a Dart 2.
