I'm no pro at this but I'll toss in my 2 cents...

I spent a lot of money on a higher-end one from AutoXRay after I had borrowed one of those from a former co-worker and liked it. It was a lot more expensive than competing brands, but I liked the features it offered.

Then I found out that the expensive one I had bought is basically useless (just gives numeric codes when MIL is on, like any $30 basic scanner) unless you spend another $199.00 on a software upgrade. None of this was mentioned on the outside box.

I'll never buy anything else from AutoXRay. It's bait and switch, it's a poor value, and it pissed me off. That's my own personal experience and opinion on the matter, YMMV.