model / advice

apple eater

I am looking at replacing my carrera with a 29er. I've been looking around at what my budget can buy me and have found the following. I've read the info but i'm not really clued up about part manufacturers specs and reliability etc. Or is there something else that may be better for a £600 - £650 budget?

Any info appreciated,,

http://www.thebicycledoctor.com/product ... ack-n-grey

http://www.sunsetmtb.co.uk/shop/index.p ... ory_id=149

http://www.sunsetmtb.co.uk/shop/index.p ... gory_id=69

http://www.sunsetmtb.co.uk/shop/index.p ... gory_id=69