It was 6am, I fell asleep. Their mouths line up pretty well though, for all sorts of fun times. And teleportation makes them always there when you need them. RIGHT where you need them.
Under those military fatigues, they're close enough to human to fill all the roles needed. If you're lucky they may even have some practical cybernetics to enhance the experience.
And don't even get me started on Turians.
With tusks.
There are certainly ones that don't have humans.