I have not looked at other tuners for the HEMI powered vehicles. I have two such monsters and both realized significant gains using the Predator coupled with basic mods such as an intake and exhaust.
I like the Predator's online upgrade capability, fuel tuning options, the CMR tune availability (done on a dyno by a DS authorized and trained tuner), DS's warranty and their technical customer service support.
With respects to my Ram HEMI, here's a link to the actual before and after dyno results to demonstrate the results realized. There are quite a few pages in that thread so this link will take you to that specific page:
I also have a Predator on my SRT and I went from a stock RWHP number of 358 hp @ 5850 RPM (peak), to 381 RWHP @ 5850 RPM (peak) with the canned 91 octane CAI tune to 411 RWHP @ 5850 RPM (peak) with the CMR dyno tune and I can tell you not only is it a numbers improvement, the torque and HP curves come on sooner and are sustained longer. It really launches the car well (4200 lbs dry), it pulls hard up to my preset shift points and you'll note that the same result was experienced with the truck HEMI. I can tell you this, you really feel it!
So, my recommendation is the Predator (unless you want the driving coach and real time monitoring functions, which are available on the DS Trinity) simply because it works and works well.