I'm a bit of a tool snob and having said that, I would consider Craftsman the bare minimum quality level to consider. Their wrenches and sockets and ratchets are great for consumer use and even most commercial use.
Where you really appreciate high end tools--Snap-On and Mac is when the wall thickness of Craftsman sockets or box end wrenches will not fit between a nut and something adjacent to it.
Or when the cheaper wrench (even an ocassional Craftsman) doesn't fit the fastener as tight as it should.
The steel in these wrenches is better and this permits them to be thinner. Their quality control means that you are more unlikely to round off tough-to-remove fasteners.
Another example of how good design increases the usefulness of fine tools is in hex drive sockets. Snap-On uses a roll pin to hold the hex drive part to the rest of the socket. It can't come out. Craftsman uses a little hex drive setscrew to hold the parts together. They constantly come apart and are a nuisance.
I've gotten to where I don't want to use a Craftsman screwdriver for anything but a pry bar or for screws that aren't all that tight. They just don't fit screw heads very well and make it easy to damage the screw head. Snap-On's screwdrivers fit perfectly.
I wouldn't even consider a set of tools from any mass merchant other than Sears. These companys aren't likely to even offer the same brand of tools five years after you buy them. Where do you take it back to then?
Also, will you knuckles thank you when your wrench breaks and they slam against the alternator? Will your knuckles know that you can get a new one just by showing up with the broken one?
Sunday I stopped at a rest area by the interstate. Some men were trying to remove a rear wheel from a truck to change the tire. When I went into the building, I saw that they had a "cheater" on the ratchet because the nut was on so tight. When I came out, the ratchet had broken and they had no other way to get the tire off. Do you think that they were comforted by the fact that they might be able to find a store that guarantees this junk ratchet?
Buy good stuff--pay the stiff price--and you'll only pay it once.
Buy junk (and with rare exception, mass merchant stuff other than some Craftsman is junk) and you'll pay in lots of ways.
This doesn't mean that a relatively inexpensive tool is not useful. You have to consider the application and the tool's suitability to it. But your base tool set--set of combination wrenches, ratchet, sockets, extensions, should be Craftsman at the very least.