Started taking my sentinel through ME2 this week and I gotta say I'm really digging the class. Very versatile, truly a jack-of-all-trades. Shields? I've got overload. Barriers? I've got warp. Armor? I've got AP ammo for bonus power. My shields just went down? I pop tech armor again and they're right back up. Once he gets assault rifle training from the Collector ship he'll be a real powerhouse, but in the meantime the Locust SMG from Kasumi's loyalty mission is doing the job just fine.