The "Deore stuff" on the Genesis is the chainset, which is a M590 Hollowtech 2 (excellent quality budget chainset) and the front mech and cassette. It has an SLX rear mech. The SLX M666 brakes are about as good as you can get for the money. Basic wheelset, but perfectly competent. (cup and cone hubs, so you'll need to service them regularly) Nice bikes Genesis, no doubt about that, and it comes with a superb fork.
Whether you want a 29er is up to you. Specialized will never compete with Genesis at any given price point, they'll always be premium price (or a specification stage behind the competition for the same money. ) Why Spesh? There are many other better equipped 29ers for a grand. Check a Cube Ltd SL for 1100 quid:
http://www.hargrovescycles.co.uk/products.asp?partno=46244
... or take a punt at a Canyon grand Canyon for a penny or two more, with an absolutely stunning spec:
http://www.canyon.com/_en/mountainbikes/bike.html?b=2545
Only you know whether you want to ride a 29er. Those who have them swear by them, and according to the "the pundits" they are outselling 26ers in the States.
