It depends on how you apply polish.
In general, 1500 grit base sanding + polish (NOT Storm's "1500 grit polished") has the same oil handling ability as 500/1000/2000/4000 grit (different from 500/4000 grit) but it hooks slightly earlier, with slightly less backend, and handles carrydown slightly better.
Some people tend to use so much polish, press so hard for such a long period of time, over a 1500 grit sanding, that they might as well have sanded to 4000 grit and applied polish. They make the micro-abrasive in the polish sand the peaks AND the valleys to something in the neighborhood of 5500 grit, maybe higher.
In general, when you apply polish over a 500 grit or a 1000 or even a 1500 grit sanding, you want to see the sanding lines underneath the polish. What polish should do is make the peaks finer, smoother, while retaining the deep valleys caused by the base sanding level.
(NOTE: Remember that polish is not a coating applied over the ball; it is just a smoothing of the peaks by means of a micro-abrasive.)
So you can use a compound, or a polish or a super-fine 4000 or 5000 grit pad to smooth those peaks. It depends on what you need/want to do and your skill level.
The more rev dominant you are, the more important the degree of finesse is, in applying something to smooth out those peaks. The more speed dominant you are, the less important this is to your game.