i just bought one a few weeks ago and put it in my 90g (the entry model 6060). although the hype had me expecting moreflow, i was impressed in some other ways with this pump that i was not expecting.
i don't think one small stream pump would be enough to satisfy all my flow needs but it definately stirs the pot.
i have plenty of flow now with an additional gen-x 6000 running the sump and also another Gen-x 4100 running a SQWD.
in hindsight with a full walllet, i would have bought the smallest tunze stream with a controller and had just one small pump running the water to and from the sump.
all in all, i really like the stream pump and find the price tag to be fair if this product continues to perform in the present manner it is in my aquarium... the sheer volume of water agitation it creates is pleasing
and i can say this, i know this stream pump creates more flow than most guys are running in a 90g. i am finnicky about flow and am a more is better kind of guy.
it could be more than you are wanting, if you have a lot of soft corals and no wavemaker then your corals will sway to one side, etc.
sorry to ramble, there was a guy that put a tunze on a pump actuator and thus created an occilator.. let me see if i can find...