In reply to Alex90: Alpine North Faces are very 'condition' dependent so the grades can vary by quite a large amount.
As ALC has commented, the Schmidt route on the Matterhorn North Face can be about 4 on average, although when I did it, it was heavily iced up, which made it harder, but also much better.
As for the Eiger well it can be anything from VS/HVS, to impossible - although that could just be my own personal experiences of 2 horrendous attempts
The general rule of thumb on North Faces, is expect the unexpected, and in poor weather, grades go out of the window.