Their PCs are regularly reviewed on PCA (a search click here), so should be OK. Let someone else confirm with their own personal experience.
Cougar-Extreme (CE) click here get very good reviews on the forums, but the best value is Dell. What kind of PC are you looking for - your usage, & complete spec you're thinking of? £750 is a lot of money even if you're not a poor student! I could possibly spec one up for you online for less, or at least get you the best value for the money. G