I have tried, and still have them both on my 07 5. 9, and still can't decide which one to sell. Both work well, but each is better suited for a different need.
The Edge with Attitude is way better for towing, because of the controllability and maxium set-points, especially on hills at high altitudes like here in Colorado. You can tow safely with little worry using the Edge with the Attitude. The Edge is very clean and conservative, with very little smoke.
The Smarty makes way more power than the Edge, almost instantly. The Smarty will definitely make you and passengers say "WOW!". But if you tow with the Smarty, you are going to break something if you aren't careful. Also the Smarty can be smokey if you don't control it with your right foot.
The Smarty is also easier to "install", but you can't just turn it off or change the power level with a switch like the Edge. Instead you have to stop and do the 5-10minute reload.
It really depends on what you want to do with your truck, Tow or Drag Race...