This is a real complicated question. The most sensible answer is there is no exact answer.
I would say that most technicians when considering your question with your level of need would say the Snap-On.
My favorite overall scanner is the Vetronics Mastertech. It is the factory scanner for Honda and Toyota and a couple other Asian cars I don't pay much attention to. It was created from the TechI scanner that was the factory GM scanner up to 1991. Vetronix developed the software for the Tech2 (GM factory scanner to current) and have most of it running on the mastertech so it does almost everything on GM that Tech2 does. It also does a resonable job on engine, chassis, and body on Ford and Chrysler. Tech2 IS the GM factory scanner from 1991 on and is the most sophisticated program available for under 3k, but it only works well on GM and Saab.
Baum works well on a number of euro and Asian cars, probably because of Mastertech they don't do Honda or Toyota (big hole).
AST does a number of Euro cars, don't know whether they do any Asian cars.
I have all the above scanners, with various modules to fit the coverages I need and desire doubles of. I also have a number of factory scanners.
Aside from these real good, solid, available used, scanners there are a number of new guys on the block. As I pointed out above I think the x431 scanner may be the best bang for the buck:
www.x431.com
It appears to me that it does about everything but domestics and I used it on a 99 E430 and it saw every module on the car. it only pulled fault codes on the samller ones like door control modules but on the engine it graphed values and had all the major menu items including programming. I didn't do any so I can't say how it works. Its too new for used but its price is better than any of the above and coverage is a new era.
These are all professional tools.