Authors should have the choice of onomatopea or descriptions. It is all up to them.

Two caveats - an overlong onomatopea, spanning more than one typescript line, will ruin any page setting; in that case I often 'slash' them to tinier bits, allowing the word processor to do its thing. And interrogation or exclamation marks should NEVER extend beyond three. (in fact I also have a rule they should come either alone or in threes - never in pairs. But that's me.)

I like the fact that BDSM readers are very much into those stylistic debates. When I read the 'ten' mark explanation in the 'review the story' submenu, I always get mad - 'is almost as good as a published story'. How preposterous... Most stories on this site are WAY better than the thin pablum found in scruffy bookstores.