Originally posted by FormulaRX
The guy yesterday told me to go buy the bike first and then go to the MSF course that way I can learn on my own bike.
Translation: "Buy this 600 from me NOW!" or "Gimme the cassshhhhh!"
As you've realised, learning on your own bike (assuming you were actually to buy a new 600) is not necessarily the smartest thing to do. I'd almost bet money that you'd drop the bike at some time during the course, simply because they're not the best bikes to learn on.
Bikes are pretty much all the same to ride - so once you have learned to ride one (say, a 250), you'll be able to ride them all, although some may take some adjusting to.
The best bike to learn on is one which is very manoeuverable and light, which is exactly what 250s are.
Learn to ride the bike slowly (ie: at walking-pace speeds), and practice U-turns, circles, figure-8s, and riding in a straight line at very slow speeds. You can pick up the higher speed stuff later on, as you progress with your riding. No-one goes straight out and rides well (if at all) at high speeds anyway. It takes practice and experience.
If you go on any group rides, you will probably be left bahind a bit (to start with, at least), but if you've practiced your low-speed stuff, you can make everyone else shake their heads in disbelief when you do a u-turn confidently, while everyone else is doing three or five-point turns.
Being able to do the slow speed stuff
does make you a more competent rider - you gain a better understanding of how the bike works, and how to make it do what you want it to. It doesn't always transfer directly to high-speed riding, but it is applicable to about 99% of riding.
Anyway, get the 250 of your dreams (

), practice riding at low speeds, and show everyone else how crap they really are at riding, because they may be able to do 150mph on the highway, but they won't be able to do a u-turn in the width of a street, and you can laugh at them for that.