A nice video by Trackman demonstrating how to do driver fitting. Lately, Brian Manzella has really been singing the praises of Trackman, mainly as a practice/instruction device. This video delves more into the Trackman.
Recently there was a golf article stating that JB Holmes and Tiger Woods had the same exact swing speed. But the reason why Holmes hits the ball so much further than Woods was according to Trackman, Holmes hits about 3 degrees up with the driver whereas Tiger hits about 3 degrees down on the driver. This goes against the common Homer Kelley principle of 'hitting down' with all of the clubs. You still hit down with the irons, but with the driver you're *best off* hitting very slightly up on the driver (although hitting down on the driver can work, you just lose some distance.
I'm planning on getting some new irons in March and will use Trackman to help fit me. Although a warning, Trackman is still hard to find as it costs $28,000 plus $300 a month. Fortunately, I have a clubfitter that has Trackman. And then down the road I'll look into getting a new driver (although I like my current driver).