yahoo was my first email account (if i'm not mistaken at that time gmail didn't even exist), now i'm using yahoo and gmail simultaneously
all gmail incoming emails is being forwarded to my yahoo, i wouldn't feel safe to rely on only one provider
i almost never give out my yahoo to anyone, however i prefer gmail by now
i'd never suggest to use hotmail for a personal address to anybody, i just don't like it for some reason (it's ok to use it for bh purposes like classifieds posting), i'm using an old yahoo account for my msn lol, this shows pretty well how much i don't like hotmail
btw what you're doing with gmail & outlook (creating backup), it's a wise thing to do