Actron CP9410 PocketScan Plus

Pros:
Easy to use, intuitive functions
Quality housing/Good Value
Detailed Instructions
Was able to read error code and erase in a matter of seconds

Cons:
None that I can think of, really.

This is a truly wonderful tool. In my area, it can cost $ 75 just to have a mechanic hook up your car to his "pro," style scanner to diagnose a problem and or turn off the check engine light. I used the scanner on my 98 Volvo V70, found that the problem was trivial (from a loose gas cap,) and turned off the check engine light. It took about 10 minutes to read the instruction manual and discepher the codes.

I was tired of either wasting my money at the dealership or going to autozone to check why my CEL was on. This obdi scanner is as easy as they get. I recommend it and the price was great.

If you get the dreaded CEL and need to know what is causing it to illuminate, this is the tool for you. Designed for the home mechanic, it is complete with easy to use interface and large display. (great when you don't have your glasses on). I had a code in it that did not show up in their online database. I found it though, searching the internet for more Honda codes. Once you get the code, you have the option of clearing the MIL, which turns off the Light. Only shut off the CEL once you have solved the problem.
The tool also gives you all of the Readiness Monitors status. So, you can tell when it is OK to go for the emissions test.

Easy to use and doesn't require a battery (but you can add them if you want to save your codes). I was able to turn off my check engine light and then check back later to make sure that I had driven enough for all the sensors to acquire the necessary data to pass emissions testing (after a normal driving day to and from work). Even if I only need to use this once it's less than the cost of having the dealer plug in their code reader and tell me what's wrong.