Hell, I just love MESH computers, I love looking at them that is, but I don't trust them (the computers, not the company). I've seen too many late delivery, problem, things not working, threads to direct my money their way. Maybe if they had a local outlet round my way, things would be different, but they don't. Davey (from Mesh) on the Comsumerwatch forum does his best to remedy any problems that do arise and he succeeds. I'll stick with my HP Compaqs bought from local outlets, they have never let me down.
But that is a nicely specced PC you linked to, stroudgreen. Sorry can't advise you on how good it would be at games, I'm a devout non-gamer.