A rainy day in New Brunswick, Canada had me playing around with a very quick set up (under 15 minutes) just to test some lighting options. Two set ups, one coming in around $500 (including stands, trigger, speedlite & modifier) and the other around $3000 (including the same types of things). The modifiers weren't 100% the same, and I should have adjusted the distance to equal the softness, but again this was a quick set up, and I was just playing.
I will repeat that this is a super quick and simple set up. I wasn't attempting to make fine art or even a portrait. I wanted to see the light different with a relatively similar set up. The most noticeable different is the colour temp for each, with the speedlite setup being the cooler of the two.
So, if you don't need certain consistency or speeds - save your $ and go for the more cost effective option.