Ruby Python wrote...
Anybody else in here gonna be playing as quarians when the multiplayer comes out. My shep has always been an infiltrator so I wanna know if any Engineer-sheps can fill me in on the combat differences.
I've played as engineer, but not as infiltrator, but I doubt the comparison holds anyway, since Tali's talents are not the same as those of an Engineer shep.
In ME1, Engineers can only use a pistol (bonus talents gained from achievements notwithstanding), while Tali uses a shotgun. Tali's tech skills are electronics, damping, decryption and hacking, while Engineer shep also gets Medicine and can specialise into a Medic after the rogue VI mission.
In ME2, Engineers still start out with only a pistol and Tali still has the shotgun. Tali has combat drone, AI hacking and energy drain (when loyal), whereas Engineer shep has overload, incinerate, combat drone, cryo blast, and AI hacking.
Incinerate in particular is a great skill when the player has it (I found it hard to use effectively with Mordin, who also has it); it does damage to anything, shields and barriers included, and travels in a curve so it can go around cover. I rarely shot my gun after leveling up incinerate.

When I replayed ME2 as a Soldier, incinerate is the power I missed the most.
The biggest downside of playing with an engineer Shepard is that it rarely makes sense to take Tali with you on a mission, since her powers are a subset of yours.