I went with Innova 3160 for its ability to read ABS codes in addition to engine trouble. My initial trouble was ABS, reason I bought it off Amazon.
It can also read live data and perform key on engine off and engine running tests. You can read data in situ or store and download live data to a computer program, though the included CD program has limited utility in my opinion.
You still have to look up the code definition and decipher "what it all means."
The definition is not in the program; I made a printout of code definitions. Innova has a website where you are encouraged to pay $14 for the most common fixes for your trouble code; I've never done this.
To download stored live data to your computer you'll likely need a serial to USB adapter cord. You have to screen capture to save graphs as pictures and trim as appropriate; one of the program limitations.
I've been quite happy with mine despite limitations. Its saved me more money than I paid. I use it on a 96 XLT AWD 5.0. Some have reported troubles but I have not had any.
example: I bought the vehicle used with ABS light on. Dealership said $1700 to replace HCU. After resetting stored codes, ABS light was due to driver front wheel speed sensor. About $55 delivered. They never tried to reset codes and assumed they would have a hard time selling it.
I would encourage you to read reviews prior to purchase and insure whatever you purchase will work on your vehicle. I do like the Amazon reviews for this reason.
Link to reviews
http://www.amazon.com/Equus-3160-Pr...UGVI/ref=sr_1_1?ie=UTF8&qid=1307720525&sr=8-1