I'm prolly one of the only two people around here that are qualified to answer this with personal experience...
I have two vortechs on my tank right now.
I used to have tunzes... Before that I tried maxijet mods. I had been planning on using a closed loop, but that never panned out and so I went with the vortechs and so far love what I see.
The vortechs don't need a controller, as they talk to each other wirelessly. They provide flow and can create an actual wave in your tank. So it gives you the flow of tunze powerheads and the wave action of a tunze wavebox.
Very lil heat added to your system as the motors are outside of the tank. As for directional flow, you don't need to direct the vortechs. They have a MUCH MUCH wider flow than any tunze I've tried. I actually wish the flow pattern wasn't so wide!
To answer your question though, you will need two mp40w. They will communicate with each other and synchronize their wave patterns. One will be the master and the other the slave. You can set the slave to mirror the master or to do the opposite of the master. Frequency of the pulses is also controllable as you can adjust the range of flow from 100 gph to 3000 gph. The flow will ramp up and down as much as you like and as fast as you like. You can tune it to your tank's frequency and as such get a lil wave action going. There are various different set patterns you can choose from as well...
All in all a very interesting pump. I wouldn't say they are "better" than tunzes, they simply provide a different type of flow pattern with some advantages over tunzes and some disadvantages in comparison as well.
Here's a short video clip:
http://youtube.com/watch?v=rLPmea2II-A">http://youtube.com/watch?v=rLPmea2II-A</a>
Just skip to the latter part of the video to see the wave :).