I think I should have bolded "my setup".
Here are the details: I had Art build me a big bore motor, on pump gas compression, with an MSD Enhancer.
A year later I bought an ATP Flame total loss, went to higher compression, and had Art update the porting to account for those two. Performance was increased some medium amount. Then I bought a 140 mag pump.
With that addition, the ski hit drastically better everywhere in the power band and and had noticeably increased top speed. Acceleration got downright violent. The performance gained with the addition of the mag pump well exceeded what I gained from just the ignition and higher compression.
I can't comment on what a mag pump would do for anyone else. I had expected better hookup and better white water performance. The increased acceleration and speed were not expected, but more than welcome. I think it tied all the other performance upgrades nicely together and put the power to the water.
I would go as far as saying that the gains are most noticeable in flatwater, not in whitewash.