i would not get a bike over 500 for my starter. I started with a ninja 500 and it was a great bike. Plenty of balls to have fun, but it didnt want to race up to the triple digits all the time. as for seeing if they are ok, question the owner. Ask if they have ever wheelied it, dumped it. Check matinence records if they have them, check bar ends for scratches.
When riding just be conservative. Constantly be thinking of where you want to be on the road to give you the most time to react and best route out of trouble. Realize that your contact patch on the ground is like 2 square inches, and you need to keep that under you. Painted lines are a killer in the rain, stay off them.
And to reiderate. If you were my friend I would tell you NOT to get a 600. The starter bikes do not drop in value too much over time, and you will be able to get a year or two under your belt and sell it and buy a larger bike.
Finally, don't get cocky, it's too easy to push your limits and get lucky. I have been riding on the road 3 years and i've almost been cleaned out by other drivers about 10 times. My dad used to ride his bike yearround in mass, and after 15 years, went over the handlebars at 70. Keep your head, and just understand that it is one of the best things you can do in life, but it can fuck you up.
