I've always like the idea of an all in one (mild polishing abrasives w/ LSP protection), especially for single stage paints, and I started using OPS (optimum poli-seal) earlier this year. This sort of product IMO is perfect for daily drivers and trucks that you just want to look decent and be protected. I just picked up some 3D speed to test against and here is what I found:

Decided to try out my new Flex 3403 lightweight rotary (1st time with any rotary) with LC white pad.
Wanted a quick test on something that would show good results for what I'm after with this type of product so I did half/half on my 7 y/o, never maintained truck toolbox (black powdercoat).
OPS:
Initially looked like less (no) dusting, though slightly harder to cleanup (marginal)
Good durability (~2months, known from previous use on an outdoor only-vehicle)
Good cut (fine polishing) ability for what the product is, pretty good swirl removal on the other vehicle I've used it on that lives outdoors.
Slight chemical smell, not bad at all.
Slight yellowish stainig of white pads, liveable
--Overall, what I wanted initially.

3D Speed:
Slight dusting, but easier wipeup than OPS
Unknown durability so far
Better cut than OPS and finishes just as good
Grape smell (normally I don't like grape smell, think Dimetap, but this was actually ok)
Pink staining of white pads (My biggest complaint about this product)
--Overall I like it better than OPS, though both are great products.

NOTE TAPELINE DOWN THE MIDDLE: