I think we're talking about two different Windows Live Mails here..
UB - presumably the one you're talking about is the web based one (essentially hotmail). In answer to your question by "fast" they mean broadband. I haven't really seen it much, but it seems to be ok - perhaps someone who uses hotmail and has upgraded could provide more info?
Just to confuse things, Microsoft have released a new program fairly recently called "Windows Live Mail" which is basically a new version of Outlook Express. Looks nice, and seems to work well, I'll probably end up upgrading at some point in the next year or two
However, over the years I have tried all manner of mail programs and always end up going back to good old Outlook Express!! Dunno why, it just feels the most comfortable to use to me. Weird.