What would be a good and reliable scan tool.

What would be a good and reliable scan tool that will do ECU coding for under 500$?

I can't make a recommendation, but for those that can it would help if you mentioned which vehicles, or management, you would want to use it on? Some are excellent for some vehicles but don't support others.

That's the thing I'm trying to find one that will work will work with wide range of vehicles. But for personal use of would be mainly GM Vehicles.