My only consideration now is the putter as I had always envisioned buying the L70 Phantom but have been using the L59 Sabertooth and to be honest, the difference seems minimal awith the Phantom only having the better balance, how important is that!? Am I better sticking with the Sabertooth until I get to L90 +!?
I absolutely agree with MarchieB above. I would stick with the L59 Sabertooth.
While I think a putter can make a difference, I personally think it's the club people place too much emphasis on when upgrading clubs.
I think the L59 putter will serve you well until you get to L98. Then I would upgrade.