I know it's just going to be one more voice in just one more thread concerning the Adept, but I'll throw my two cents in anyways.
I began an Insanity playthrough with an Adept shortly after beating the game on Veteran with a Soldier. It's tough to go back and play a Soldier after having the ability to sling powers around corners, so that definitely says something for biotics.
However, as has been said ad nauseum, the overuse of the Warp ability really dumbs the class down. When fighting on Insanity, I use Warp, Warp, Warp, Warp, and when the defenses are down, do a Pull/Singularity + Warp combo. That's not terribly interesting, even if curving powers around corners is cool and fun. It loses something when it's the same power over and over.
It also stinks that the abilities are more or less useless until the enemy is defenseless. People have overexaggerated and said once their barrier/shields/armor are gone, enemies are one shot kills. That's not true without the sniper, nor is it as useful as lifting them in the air and blowing them up in the midst of your enemies with a Pull + Warp. However, it is true that having to shoot and Warp an enemy before actually being able to use your collection of other abilities sucks. It's just not terribly exciting.
I also dislike how now, with the global cooldown of abilities, I can't do a quick Pull + Throw combo by myself. I either have to sit and wait for the abilities to cooldown, or use a squadmate's Pull or Throw. I applaud the attempt at forcing me to use my teammates more, however it stinks that I can't pull off a slick combo alone. After all that Warping and shooting to get them down to where I can use my biotics, I wish I could finish them off alone with impressive fashion.
Overall, there are some very fun aspects to the class. Curving powers around corners, having a ton of active abilities/spells, and blowing up biotics are all really cool. However, the rest of the class feels so restrained that it just doesn't shine. On higher difficulties it's more frustrating than rewarding.