Difference between Firm Flex graphite and Stiff graphite

Question
I have a Titleist 975 4 wood (16.5 loft) with a UST ProForce 65 "Accelerated Tip Response S" and an Adams Tight Lies 5+ wood with a Firm Flex shaft.  Neither are as rubbery feeling as a regular flex graphite shaft (and I had an Adams GT3 5 wood).  They're both exactly the same length.  The Adams is rather easy to hit off a decent lie; the Titleist, I pretty much have to have my swing mechanics in order and it normally has a pretty high trajectory.

Answer
Lou:

All shafts are different Lou.  It doesn't matter what it says on the lable.  Hit them for yourself, feel it, sense it and watch your ball.  Once you find one that "feels" good, buy that club.  Don't order one, it won't be the same feel.  Shafts are really funny but it's hard to find two exactly alike.

Eddie