Very easy to use. Just follow the directions. Received the BullyDog BDX one evening and had my truck programmed the same evening. There are several settings. I only chose a couple to begin with, but noticed the extra power immediately. Ibis will it set in economy right now, but I haven't noticed a tremendous increase in mpg yet. I mainly got it for towing my camper which is 37' bumper pull and weighs 8800 pounds in the dry. So far, I am very pleased with the BDX.
Issues with desktop program
There seems to be several people who are having issues with the program loading on their computer. The customer service is decent. They were able to install the basic tune on my programmer but I still don't have access to the computer program I need to load other custom tunes.