I used them a couple of times over the years..they may be better today but my experience was that they were a total waste of money. Increased power only was available above 3-4,000 rpms....I don't drive in that range.
They work great on a diesel, but not much help on gas motors. The biggest benefit was the change in shift patterns for towing, but then I wasn't happy with noon towing performance.
I agree that the engineers today at the manufacturer do the best job of designing the programming for most situations. If you are racing, the after market stuff can be beneficial.
Plus the cost is really over the top imo....