Now this is from my experience with all 3 tuners. I first started out with superchip 3865 loved the tunes when I had my basic intake tune exhaust headers no cats. The only thing I did not like as you see later is the custom tunes. But enough about me here my review
Superchips has better transmission control than the predator (unless you get trans tune which they don't offer), and if you're just planning minor mods like CAI, exhaust, headers, bigger wheels, etc. then the Superchip is the better way to go. It does not support any custom tuning, just the canned tunes which are great in most cases. You can adjust a good amount of item in it. Don’t quote me I forgot but I don’t know if you can turn mds off I forgot.
Now onto the Diablo Predator is the most comprehensive tuner on the market with custom tuning applications for heads/cam and other engine modifications (more "built" higher then basic mods). It does all the same things as the Superchip, but with more capability if you ever want to do more. Superchips spent way more time developing the tranny functionality then diablo. They truly make sure everything works before they release if SC had custom tuning (which they promised at one time), I would still be running that today. I need the Diablo for custom tuning my cam/heads combo. Also, after talking to some very experienced users. When you revert these tuners back to stock, SC leaves no foot print, diablo does from what people said (But They never seen it from mine).Both tuners lock themselves to the car, so only one car per tuner. Here is my opinions (based on a lightly modded ram)...
I would say from seat of the pants, the predator (diablo) provides a more fun ride, but the superchips is a more refined ride. The predator is almost too aggressive, shifts to hard, etc. for say just driving the wife and kids to the grocery store. Out of the box, the superchips will idle better, not run the fans, etc. with basic mods I liked superchip ALOT! You can fix all that with the predator, but you have to change all the settings by hand (up the idle, change the fan speeds, etc.)
If you are not driving the wife and kids to the store, the 1-2 shift at wot with the predator makes it totally worth having. When I am horsing around that 1-2 shift puts a smile on my face every time. The diablo also gives you a lot more tuning options, but you probably won’t need them if you plan on staying bone stock.
I found either one to be better than stock. Both of them give me better gas mileage, fix the shifting issues and get rid of the lag between pressing the gas pedal and actually feeling acceleration. They both add some horse power (the predator seems to add more) but that isn't as important as the fact that they both apply the existing horse power better. The predator is easier to use (menus and software wise) but kind of a pain because it needs external power and an usb cable to update which I feel diablo update more than superchip done. I've had no end of trouble with the superchips getting it to download updates. The predator, so far, has not given me an issue. Personally, I am staying with the diablo. That is mostly because I know I have bunch more mods in my future when the warranty runs out on my car. At that point the custom tune you can have done with the diablo will be a must. Honestly, you will probably be happy with either, and you can probably pick up a used superchips pretty cheap right now.