I have used both and I like the penguin penductor's flow charecteristics a little more as the orifice is slightly larger and I think it actually flows a little bit more with slightly wider dispersion of the water... however, I changed it out because the pacific coast flow accelerator really just pops onto 3/4" locline without any problems and thus saves a little space in my 60 gallon cube and is more maneuverable.
The flow accelerator actually comes with a small length of "loc-line", but it's knockoff loc-line that is not as good as the real thing and you'll find that the flow accelerator is a much tighter fit on the real loc-line.
By the way, I run one of these off of a Mak4 pump and it puts out a substantial amount of flow, the only thing is that I wish my tank were longer since I feel a lot of the flow is wasted by bouncing off the walls of my tank.
Also, when they say increase by 400%, I think you've got to realize that you aren't going to take a 1000gph pump (pressure rated) to 4000gph. You might boost up flow to 2000-2500gph secondary to the eductor effect (bernoulli's principle), because the eductor severely cuts back on pump flow, so that 1000gph pump is actually only putting through the eductor around 500-600gph.