Mammoths, after all, were vegetarian and so would be unlikely to pick up the bad T-rex habit of eating people. Which would be of no consolation to you should you be underneath the foot of a mammoth that had broken loose from its enclosure and was rampaging around the countryside, but at that point our interest level in what you thought would be kind of flat. Heh.
Plus, unlike scaly or partially feathered reptiles, some really wild results could be achieved with a couple tons of hair mousse.
The plan, once scientists locate a well-enough preserved sample of soft tissue from an iced mammoth, is to clone its DNA by inserting into the egg cells of a Mrs. African Elephant, and then wait out the 600-day (!) pregnancy which should produce a wooly mammoth calf. Scientists do not indicate what they will say to Mr. African Elephant when he queries his mate on the fact that their new child does not look anything like him. A possible response might be for the missus to point out the calf doesn't look much like her either. I suspect that Dr. Phil may have to be called in at some point.