The N12P-GT1 is an overclocked GT 550M according to several review sites. Lenovo lists it as the GT 555M. The i7-2630qm is a quad core CPU as opposed to the dual core i7-2410m.
Specs wise, the HP is better, but they have quality issues. There have been several complaints against many HP models and there are some class-action lawsuits in the works against HP.