User blog comment:Avg Man/Insanity Help/@comment-1388547-20120720013148

If you have a decently leveled Adept (ME2 import or ME3 New Game Plus), you can breeze through Insanity using biotic combos. My first Insanity playthough was with an Adept, and even on the highest difficulty level available, she still felt overpowered, especially with Javik and Kaidan along to combo with. I'd recommend taking Energy Drain as your bonus power to deal with shields, but it's not as vital as in ME2. A Sentinel can do the same kind of biotic combo play, with the disadvantage of slower cooldowns (if you have Tech Armor turned on), but the advantage of having Overload innately, allowing you to use your bonus power for something else.

For non-biotic classes, the Infiltrator is very powerful, especially once you're able to buy the Black Widow. The only place I felt seriously challenged in my Infiltrator Insanity run was on the final battle in London.