Re: Fleece as good as wool?
Fleece is similar, but not the same.
It can breathe, but many mamas report that it does not breathe quite as well so in summer their LO will be cooler in wool than in fleece. However, it still breathes better than PUL.
As far as leaking through, fleece won't hold any wetness so if the diaper is soaked the wetness will pass through the fleece. Wool can absorb a little bit of wetness before it passes through.
Care: fleece is very simple, you just toss it into the laundry -- ANY laundry. Fabric softener can help it stay soft and more wet-resistant. It resists staining so is great for playing outside or eating, etc. Wool requires more specialized care, but you can use it for several days before you need to wash it.