don't know the ins and outs too well, (what to look for, what brand does what) but I own the auto x-ray techscan7000. It retails for better than 500, but If you shop around you can find deals online. I got mine from tooldiscounter.com for under 350. I've used it on literally dozens of cars and have yet to find something it CANT do. abs and foreign obd1 are supported with different accessories, which you can buy online as well.
It's my first scanner so I'm by no means a pro, but I really am impressed with my ax7000.