Windows Live Messenger is pretty much exactly the same as MSN 7.5 . The main differences in it is that there is more advertisments; a different colour sceme; The ability to VOIP and thats about it. Nothing much seems to be gained by putting this out. It also looks to be a way to get money from the stupid little kids who accidently VOIP their freinds homephone instead of VOIPing the computer. By putting MSN Live onto the computer you end up making others not able to use MSN because their accounts are not allowed to use the beta. This of course can be solved by sending them one of the five invites you get to send to them. Is it worth it? No, unless your lucky enough to get an invite(easy). It's alot like Gmail.
"Hey Jack, I just got Windows Live Messenger!"
"Yeah way, wana copy of the download file."
~2 minutes later~
"WTF it's not working."
"Oh yeah, I didn't send you an invite and I don't have any more."