Haven't got a 7520 but I have got the the C2D equivalent model the 7720.
Admittedly I am not a gamer so don't care about fast 3D graphics but for my usage, (general office, internet and some graphics), I find it very good and it runs Vista well.
The Acer gemstone designs do seem to be quie thick which means that you have to be careful selecting laptop bags, (I se a Crumpler Sticky Date bag and it just fits).