I don't use it. I would if there was a reasonable amount of space for the free accounts. And I would if I could default reply from another account (i.e. my appleID).
(I also wish they would let us consolidate our appleID and our various mac email addresses. In other words, I started my appleID when itunes first launched. It's my work email, for better or for worse. Years later I got a .mac address, then a mobileMe address. I'd love it if I could bring my mobileMe user name into my appleID. Alas, apple didn't allow that and instead I had to create yet another mobileMe address (since all of my purchases were under my original appleID).
so, no. I never use it. Not even sure what it is these days.
My email is archived in two places, one is yahoo, one is outlook. I don't archive on gmail because I don't like their data mining.