I have not actually used either the Hypertech or the Diablo, BUT have researched and read the user instructions for Hypertech, Diablo, and Superchips Microtuner, and agree with Boosted: the Diablo easily offers the most adjustability.
Find the instructions online at either their websites or one of their dealer websites, and see for yourself.
The interface on the Predator is also much more intuitive.
I WAS going to go for the Predator after doing the research, until I found a shop here in Atlanta, where I am on temp assignment, who can do an actual dyno tune using LS Edit. That approach is superior to ANY of the storebought tuners, if you can bring yourself to spend the money ($500 to $600 from what I have seen so far), as a SKILLED tuner with a dyno and LS Edit can optimize things for your YOUR SPECIFIC engine, vehicle, and objectives, rather than using a "one size fits all" engine parameters program.
But, for those who don't want to spend the extra money, or want the ease of rapid self-service restoration of the stock factory program before they go in for warranty work, or don't want to subject their prone-to-run hot SSR to a dyno session, or just don't have convenient access to a dyno and skileld tuner, the Predator offers an awful lot for relatively low cost.
One caution I noted when I read the Superchips instructions: They noted that SOMETIMES (not always), the battery has to be physically disconnected for a time and then reconnected (see the Superchips instructions for details on when and why), which is a PAIN with our underfloor mounted SSR batteries, and certainly inconvenient if not in your own garage at the time! Presumably, this can also apply with a Predator installation, since both the Superchips and the Diablo Predator both seem to use the same basic programmer underneath the different interfaces and customized capabilities.
Jim G