Here's some details on their webpage about the EM-4 version, which guys use on rotaries.
I know there are a couple drag racers around the states using it on their engines...

http://www.sdsefi.com/specific.html

What are the pros/cons/limitations of this system?
$785 US is a good price

 

they are suppsed to be pretty good, we called and the fuel only is $700, witch is a little high

mike

 

The EM-4D is the one sold for rotary applications. It only controls fuel. You can make the other system control ignition but it can only fire leading/trailing plugs at the same time i.e. 0 timing split.