Both are good choices, however a Japanese 600 will be much easier and cheaper on parts. Neither bikes are known to break but if you put the bike down or crash odds are that there will be plenty of people in the pits that have gsxr's, R6's and ninjas that will gladly loan you a part or two if needed. The Daytona is a little more rare. That being said the Daytona motor is a gem and would be so fun on the track. If you have not tried out a Daytona on a test ride you may want to try it out first. I took a 09 model for a ride a few months ago and it was far too aggressive of a riding position for me, even for he track. It made my previous 06 Gsxr 750 feel like a touring bike. Not sure if the pre 09 models had more relaxed ergos.