puttersman: perhaps I should try another and see what happens.
The difference doesn't magnify itself until you get on the faster greens. Unfortunately, you can only practice on Very Fast greens now but Oakmont's Very Fast, with all the ups and downs there, is a pretty good place to see how much difference a putter can make.
Look at it this way. The difference between your Spider and the free putter is what it would be like comparing the Spider to the better putters. GL