I have a 5 year old hard tail Rockrider (which I am pleased with) and have seen the 120 mm full sussers in the shop.
Whereas the Rockriders look like a half decent 1st effort, I would be inclined to go for an Anthem.
Anthems have been very well rated, resale value is better (as everyone above has mentioned), but more than that you are getting a good, upgradeable frame. I would have thought it would be easier to get better second hand frame specific shocks etc in the future for an anthem too, as there will probably be more bits on ebay etc down the road.
My brother has a 6 year old anthem 2, which he rates highly. Just had 100mm forks put on it.