I have been running a Profliux AI combo since the start of October and there are definitely some pros out there and as with everything there a few cons.
First the cost is a big deal. I am running 5 fixtures but was able to get them when they were 15% off so there was a substantial savings. I agree with Xenon that Chris @ AI and Greg @ Reef Geek were both a big help with what I needed and what was going to work for me.
I have an odd shaped tank, the thread is here.
http://www.reefcentral.com/forums/showthread.php?s=&threadid=1461563
I also have an open type of aquascape which helps in the application of the AI fixtures. I have "individual islands" which I use a single AI fixture to illuminate each area. I would say each fixture is probable seperated about 1 foot from one another but when looking at the tank it appears to have an even light spread. I was worried about having a spotlight type of effect.
If getting one of these fixtures you don't necessarily need a Profilux, as it comes with a controller, but I wouldn't want to have it without the Profilux. It gives you so much controllability and simulation that it is quite amazing. Lighting storms, clouds, moon phases, etc. It's pretty neat.
Now here is the only drawback I had with the LED fixture. You can control the Kelvin rating very easy and as Xenon says you can definitely get a very blue actinic color. It really makes the corals glow. When turning the whites to 100% intensity it gives it a pretty whitish yellow color. I don't know what Kelvin range I am in with everything at full intensity but it is a little too yellow for my liking. You can bring down the intensity of the whites but at the cost of the intensity of the lighting.
My fix around this was to supplement with T5s. I ended up adding 4 x 55w Fiji Purple bulbs and it gets me right where I want the appearance to be.
Growth with the lighting has been pretty good. Unfortunately at Christmas I had to break some stuff down due to Ich and I pulled the corals out to Hypo the tank. I will see how the AI and T5 combo works for growth.
Hope this helps. All in all I think these are great fixtures and along with the Profilux you can't go wrong.