Xfire vs Steam

So I finally got my Steam account up (I couldn't remember my psn password since I made it with Portal 2 on my ps3) and except for the game support and store, is there really any difference between them at all? I've always used xfire (since '06/'07) and I'm new to Steam so right now my judgement is favoring Xfire heavily. Not to mention I rarely ever use my credit card and never link it to anything; so the Steam store is somewhat useless to me.

I like xfire because they are constantly updating their game support and their UI is simplistic, but I think the Steam UI is pretty nice too.

Depends on what your online mates use. We use skype/teamspeak to communicate, not msgrs.

Steam. Never heard of XFire, but Valve is an amazing company.