My answer is no. I just purchased the 2010 Stumpy Comp and I couldn't be happier. I was just like you debating over the carbon or the aluminum expert(actually for brief moment I thought about Enduro too ) until I realized that I don't need anything more then the stumpy comp. I test rode all of them for a few blocks around the neighborhood on bumpy roads and I know it's not like riding on a single track but I got an idea about all of them and like I said Stumpy comp was all the bike I needed.
So save your money and get the Stumpjumper comp. You'll save $1100 over the expert and whopping $2200 over the carbon.

I don't know what kind of trails you ride but unless you are doing full on downhill 25 foot drops which I know you don't because you thinking about buying the carbon frame basic comp will handle anything you can throw at it.