In my humble experience, and this is just my opinion, which can be likened to an ar$ehole in that everyone has one

i'd say the following. Having started out with a turbo nozzle, it did do the job fine, how-ever it was messy, time consuming and used alot more water, which has to go somewhere and again if the drainage on a job is poor takes more time.
I bought a mosmatic flat surface cleaner and the difference is like chalk and cheese. I'd liken it to painting a wall with a brush or a roller, the brush will cover the wall (eventually), but takes time to get the paint even and uses more paint, the roller covers smoothly, easily and uses less paint.
There is no doubt the turbo nozzle is the more powerful as the water is coming out of 1 hole as opposed to 2 on the fsc, but with the fsc's jet being applied closer to the ground the difference is usually negated and a smoother cleaner finish given in much quicker time with less water.
I think it's important to find what woks best for you and stick with it, how-ever I can't help wonder if there is a problem with a setup where the user finds it easier to clean for example brick paving with only a turbo nozzle and ignore the fsc.
Again this is only in my humble experience, but I genuinely believe a properly set-up fsc/pressure washer/turbo nozzle combination is considerably more effective and efficient than a turbo nozzle alone. Imagine facing 500 square metres of paving with a turbo nozzle

I'm no expert on how to set up the fsc nozzles etc., perhaps someone else can advise on this, but a properly working set-up is irreplaceable.