We looooooove wool, love it love it love it!! It's very rare for DD not to be in wool, we use mostly longies at the moment, either hand knitted or interlock ones, never tried wraps though. I prefer the hand knitted ones cause they're so soft, cozy and warm (I made DD a longies and hoodie set and couldn't stop cuddling her, so squishy!), but I find that the interlock ones give more protection against compression wicking when she's in the sling for a long time.
As for washing... I wash them by hand - and by wash I mean throw them in a bucket with water and wool wash, leave for a bit then rinse - and not often at all.. generally when they start smelling a bit
And if anybody ever tells you that "wool is so hot"... ask them if they'd rather wear a jumper made of wool or waterproof plastic. I got weird looks when people saw DD's wool soakers when it was really hot last summer, truth is that they're not as hot as PUL (or sposies) and let the skin breathe much better.
To sum it up - I love wool.