For me melee is efficient, after a biotic charge and nova, the enemy's hit points should be pretty low, so 1 poke or 2 with a melee weapon should do it, no ammo spent and you dont have to aim.
LOL this is my 4th playthrough, I played an infiltrator during my first 3, so this time round I am playing vanguard and forcing myself not to select from the tech tree... Still carry a sniper rifle for those architect fights though... I have to say Adepts are hard to use, good for low level crowd control(love throwing a singularity onto one of those guys jumping down from a shuttle... but it's gonna be tough to take down one of those huge nasty ones...
