James,
Last year I bought 2 glass V10 sports for my club. I looked at a lot of boats (Huki, Fenn and older spec skis) while deciding on the V10 sports. I bought the V10 sports because I figured they were, dollar for dollar, the best boats available for beginners.
Having paddled for a summer now, I would not buy one for myself. I'd buy either a Think Evo or V10. I wouldn't get a sport (too much butt wiggle - unless you get one of the Saffer models).
A quick check of the Epic website confirmed that they really are not making full Carbon boats. (Doubt any one is any more) The Ultra lay-up is Kevlar and Nomex. The Performance lay-up has Carbon in it, as well as fiberglass. The site also states the Performance lay-up is more durable.
www.epickayaks.com/faqs/?nid=670
It is true that you can tell the difference between heavier glass and lighter carbon boats. But as a newbie, it is unlikely that you'll be able to tell any difference between the perforance and Ultra V10L models. Rather, there is no chance in hell that you'll be able to tell the difference.
I'm a beginner and I love the sport. I live for our Tuesday and Thursday night races. I've had some really great people like Alan Carlson and Jeff Raymond (from Think Kayak) give me some awesome paddling tips. Because of those tips, I regularily beat people in much lighter boats simply because of technique (and my stroke isn't very good).
If it were me, I'd buy the Performance model over the Ultra. The weight is an issue, but not the biggest. I think its outweighed by the extra durability. Also you can get different coloured decks on the Performance model - helps you be seen by intoxicated power boaters.
If you really want to excell, spend the money you save on some paddling techniques and coaching. Two friends who I've beat regularily this past summer are going to do just that. I can't because of scheduling. Next summer they will stomp me. Also put a GPS unit (Garmin 305 seems to be the one of choice) on your christmas list, I have.
Cheers
Sean
PS -I'd also spend some of the money you save on your wife/girlfriend. Because if she ever reads this string of comments and you haven't got her anything... Well it was nice knowing you.