If your current driver has a TI face I doubt if you are missing out on much. The bigger heads give you more forgiveness. Some yardage gains. You have to justify the cost of the new drivers. Will the big bucks you spend be worth it?
Finding a good used driver is easy enough. You can buy PING G5's etc on ebay for half of what they sold for 6 months ago. Good way to try a 460CC driver.
Personally I prefer drivers in the high 300CC sizes. I am currently using an old TaylorMade R580 and like it a lot. My other driver is a clone of the Titleist 983K which is under 400CC in size.
Bottom line. To each his own. You might not like the "Lunchbox Driver" The next guy in line loves his.
I have read some other forums this week and guys are all talking about the NIKE SUMO and how well K.J.Choi hit it. Long and straight. They are saying "If that is what that club does for him then I am buying one" Remember folks, K.J. is a PRO. He could hit any driver long and straight! Nike just happened to luck out last week. New driver on the market and K.J. got hot and won while using it.
