Light rail/movers

Does anyone know the benifits of different rpms on light movers? Why would I want it to go faster or slower? I believe I have the fastest rpm of the three models of my brand. Is that good?

I've seen your journal, its pretty fuckin amazing. Only thing though, I wasn't quite clear on a few things. How big was your flowering room? How many plants were in therre and how much did they yeild? Also, did you go straight from clone to flowering?