For dialog, I'd mostly use like instead of as if. In other cases, I'd stick with as if when it was the grammatically correct choice unless it sounded incredibly awkward.
I've noticed interesting variations among the editors I've used. Some are sticklers for correct grammar even when I (a former English teacher) wouldn't be. Sometimes they want instead whatever flows best, even if it tramples on two or three different grammatical conventions in one sentence. For some Chicago Manual of Style is the last word, no matter what. For others, CMOS is by no means such a rigid guide. All of these people have publishing industry experience, yet their responses are not consistent.
Publishing houses normally have their own guidelines, which are probably based on CMOS but may deviate from it in some ways. Since we are all publishers, we can theoretically do the same thing--as long as we are consistent in the way we handle the same situation.