Actually they make a lot of stuff that is bad. Just not bad for the reason I believe you are implying. They do make some stuff that is just outright bad but, it is few and far between and atm I can not think of anything other then extensions, 10mm 3/8" drive socket, and pot metal direction switches on ratchets.
There are some SO stuff that I would not buy because of this. Quick Release ratchets. Other then the 1/4" and that is because of a lack of viable options their 3/8" and 1/2" **** because the button sticks out and if you bump it at all it drops. I only use quick release ratchets and try like hell to make sure the buttons are flush or recessed. 1/4" is the only one i could not get a flex, fine tooth, quick release with a flush button.
Another thing is their diagnal side cutters. They dull very fast when compared to knipex. There slip joint pliers while they hold up well are way way too aggressive in the teeth. Their screwdrivers lack a driving cap which makes them really crappy when working on rusted vehicles.
Another is their pry bars. They flex way too much as do their wrenches but, unfortunately with wrenches its hard to find anyone better.
TBH there is not much made by them that impresses me over what I can get from their suppliers or other companies. Flank Drive + is about the only thing and that was taken from Williams when they bought them and reinvented. If it wasn't patented all of the companies would be doing it and I would not own Snap-On wrenches. The newer MG325 and MG725 are good impact guns as well but, there are others that make stuff just as good if not better.
Snap-On is there for convenience and that is about all that is a major plus from them.