I am not a good mechanic, I don't even pretend to play one on TV. Mostly I am somebody who is sick of paying $80 to the local mechanic to find out the gas cap is cracked or some $10 part needs to be replaced. I finally decided to buy a code scanner to facilitate my repair efforts.---THE GOOD STUFF---* The unit worked right out of the box on both my 2006 Subaru Outback and my 2002 Jeep GC. The hardest part of the whole deal was finding the port on the Subaru. (Tip-look under the hood release).* There seems to be a whole INNOVA website that they want you to go to for help translating the numeric codes into English. So far typing every code I have seen into Google has brought back more information than I know how to use. Not sure how this works for more serious mechanics who might need access to technical bulletins, but for us Saturday morning driveway hackers, it is fine.* The unit seems reasonably well made, although not sure it would stand up to the day-to-day use of a professional. For us "couple times a year" mechanics, it seems fine.---THE NOT SO GOOD STUFF---* There are no directions included, only a CDROM. The CD doesn't even have the directions, but points you to a website. Actually it doesn't even do that, instead it loads an application onto your computer and the app has a link built into it to get you to the website. Kind of convoluted and time wasting.* Plugging the scanner into your USB port kicks off the loading of a driver. No warning, and no idea what it loaded. I hate that.* The box could really do with a quick-start guide. Really all you need to know is how to plug it in, when to power (not start) the vehicle, and what the little buttons do. Would fit on an index card. Instead it is a 15 minute software deal.---SUMMARY---It seems fine for what I want it to do, namely just scan codes quickly. The whole PC/CDROM could have just as soon been skipped. For my use, no reason at all to plug it into the computer, and the installed app just looks like trouble.Ideally a quick-start guide, or better yet, some abbreviated instructions printed on the back, would have made this so much easier for a first time scanner user. That is the reason for the 4 stars and not 5.No idea how robust the unit is, or how long it will last, but I will probably lose it or drop it before it "wears out".