P.S. How do you keep an assault squad w/ infiltrate up far enough to shoot w/o being assaulted on turn 1-2-or 3??
you don't. unless they're raptors...in which case, you don't want to stay back to shoot...you want to assault first.
missions with pushback 18" mean you will be assaulted in the second turn at the latest (first turn against blood angels or maxed out measurements from vehicle rushes -- move 12, disembark 2, assault 6). if you get first turn, you get off a few shots. but you will most likely have to back off.
savvy veterans always have some "pushback unit" of a sort. things that are frightening enough to make the opponent back off during deployment, will attract a lot of firepower, and which you won't miss when it (inevitably) dies. chaos dreads, cheap preds, vindicators, ork battlewagons and killa kans, fit the bill.
devsquads and havoc squads aren't usually good pushback units. you spent all those points on multiple (and more expensive) heavy weapons...so you WANT to shoot with them as long as possible (whole game, if you can help it), instead of shooting once or twice, and then mixing it up in close combat. that's a waste of points.