For simply caching out your sims is there any performance advantage in using a TOPs ROP geometry Output node vs simply a File Cache or ROP Output in SOPs?

Depends on if you're doing you're doing “All Frames in One Batch” or not. If that toggle is on, it will probably have the same performance as the File Cache.
If you have it off, Houdini will send off multiple Work Items at once to render in Background. Therefore using more resources and therefore faster (should be anyway).

So if you're not simulating (All Frames in One Batch) it's faster.