You are right. Once HP and SCT get a little more involved and add some of the features that Diablo has had for a while now, it should be a closer comparison. As it sits right now, Diablo gets my vote by far though. Competition is a great thing, and it may even get Diablo to step their game up a bit and add more tables to help dial in the tuning even further.
Now, I have nothing against email tunes on these trucks though because they are so difficult to run on the dyno. They always try to downshift, or run through 2nd prime, and there are numerous 6 speeds that have even lost 4th gear on the dyno because 4th gear is just too weak to hold the power that some of the heavily modified guys are putting down. Tuning on the street, or on the track, via Diablo's datalogger has proven to be very effective. You get true load, can avoid going into 4th gear, and for those of us that prep to race, it is a more accurate way to dial in the truck in race form (no air filter, no exhaust, setting proper shift points based on gear and shorter height drag radials, etc...) I don't think anyone expected us to see a N/A 5.7 Ram pushing the brink of an 11.99 pass, but I can almost guarantee you we will hit that mark in the next month or 2 (I'm going to try again this coming Friday). The track datalogs and email tuning has done very well to this point.