I leveled in Keep 2 mp9 and mp10 for awhile before switching to Crater 2.

Keep 2 seemed quite decent for legendaries, felt like I got a lot more legendaries then when I was doing alkaizer runs, downside is you don't get any essences.

Crater 2 is really good for exp, took me about 2 1/2 hours per level at plvl97+. Crappy place for legendaries though.