Not all S&W knives are made by the same manufacturers, and to answer your question, some of them are quite good for casual use. The Extreme Ops pictured below originally sold for $85, but could be had for five dollars a few years later. I bought a bunch of them to give away and YES, the quality is there for a medium grade knife. Other S&W knives are okay for ten and twenty dollars -- certainly better than Maxam and other ultra cheap knives -- and it all depends on what you pick and what you can get them for. A few years ago, I got a shot at some CRKT S-2s, which have ATS-34 blades and titanium frames for $25 each (including shipping). This was an astounding deal for a quality 4-inch blade knife.
No one brand will give you great quality and price on all knives. All Spydercos will be quality knives, but some are frankly more expensive than what I think they're worth. So you have to hunt for bargains. (Spyderco's Native was a great value from Wal*Mart, but they're no longer available for the modest price of $40.)
These Extreme Ops knives sold for eighty-plus bucks when they first
came out. I got these for five dollars each, and they're pretty well made.
The plain edge also holds its edge very well and the serrated blade has
its uses.
Another great bargain in the knife world is the Spyderco Byrd series, especially the Cara Cara. One model has an FRN handle and the better ones have G10s. Both, however, are great for the price.
Sometimes, each knife must be judged on its own merit. Cold Steel doesn't make their knives, but they exercise very good control over those who do and their knives are generally of a good uniform quality. CRKT also makes decent medium grade knives, but some tend to be a bit heavy (though strong). Spyderco makes their own knives and they make a consistently good product.
I've seen a number of S&W knives that are good for general carry, but they're not likely to be top tier knives. But they do tend to be better than many people think in thier price range. Smoky Mountain Knife Works sell many of them for around tend bucks. (These are folders, mind you.)
They're good for opening packages and general cutting chores, but I wouldn't depend on most of them for self defense. Knives have different locking mechanisms and I don't generally like liner locks unless they have a back up safety.
This Homeland Security makes for a strong outdoor knife and I think
it's generally been underrated. Friends of mine with this knife have
used it for all sorts of things and it's virtually indestructible, plus
it holds a reasonable edge. 
