On both sides of the mountain the summit day is long and arduous, cold and demanding, but not technically difficult. Mount Elbrus is quite a symmetrical volcano so the gradients on each side are similar, but the north side has none of the facilities of the south side so it's more committing. The pictures below show each route and the altitudes.
Summit day on the south side is usually made shorter because a snow machine drops people off at Pastukhov Rocks (4700m), while on the north side there's no choice but to walk all the way. There is more on this subject on the Preparing for Elbrus page.