I haven't used wool soakers before (although I knitted two for this babe for an experiment), but I did use wool Bumpy covers for ds1 and I LOVED them. I used them at night when I stopped doing nighttime changes and never had any leaks, they were awesome. So soft, too.
I never got the hang of snappi-ing or pinning my prefolds, so I didn't try any of the pull-on kind like Aristocrats (with a Bumpy you can just trifold your PF and lay it in the cover), but I know people swear by them. Never used longies either. Good luck!
Keeping busy with 2 boys & 1 girl ('04, '06, '08)