Since I am the only one here who apparently has it then I will vote yes.
The pros:
Play against real people
Talk while playing
Play as a team
Some friend support
The cons:
Lots of really immature people that currently no way to get rid of.
No clan support
Some games are laggy
The thing about Live is you have to get some guys that you play with over and over and then it is a blast. If you just get on and start playing with random people it just isn't that much fun. 90% of the people on Live are kids around 13 who are trying out all the cuss words they know or just see how annoying they can be. Luckily some of the newer games coming out like RTCW allows you to boot players. As long as you are at least playing with people you know on your team then it can be a lot of fun.