Colby I would go get sized- or should I say- FIT!! If you have a good tri shop in your area that is preferable. Lucky for me Trisports.com is located in Tucson, and they have a storefront. I made an appt and was measured and poked at every which way. Since I'm a "thick" girl my size is decieving, but I'm really squat. He said even an xs was pushing it! My limbs are THAT short!!

As for the difference in riding tri specific.... The first thing I noticed was that the front end is WAY squirrely. That took some getting used to, but I'm fine now. Also I'm on pretty steep geometry so I'm dumped down pretty low in the aerobars. It took awhile to build up the ol neck muscles.
I have picked up ALOT of speed, and I think I am fresher coming off the bike. Tho I am still SLOW! No speed gained in the running legs for this kid I'm afraid! As my coach would say "it's a BIKE not a miracle machine"!!