Also, some questions[*]Was it some weird dice rolls on my game's part that my Support soldiers were exclusively female (and that women were only Support, no other classes)?[*]I avoided S.H.I.V.s entirely - are they useful?
1: Yes it was. In my game women had about equal class distribution as men (Maybe proportionally fewer Heavies, but I got fairly few women, so it's hardly a good sample).
2: S.H.I.V.s are good. They're less versitile than a human soldier, since they can only Move and Shoot, but they move farther than most, and hit a lot harder. Plus they can absorb a good deal more punishment.

I find them especially useful on terror missions, where their increased movement speed and expendability (Since they represent only an investment of resources, rather than several missions worth of experience) make them ideal for rescuing civilians, and their increased firepower lets them handle hard targets like chryssilids.