A tool junkie's thoughts on sockets...
If you just want to turn a fastener with the least possible expense, almost anything will do. Sometimes you need a "disposable" socket that you can grind or weld to fit a particular application, in which case - well, you probably have a Harbor Freight store nearby.
Over the years I have evolved my approach to buying tools from "what's the cheapest" to more of a "buy once, cry once" philosophy. That's certainly not to say that I always go straight to the Snap-On truck (though the Snap-On guy would be happy if I did)... but I'm not afraid to spend more on a tool if it provides a corresponding value, is a pleasure to use, and is likely to last a lifetime. Not everybody feels the same way or is in a position to do so - it's down to personal preferences and circumstances.
What I'm getting at is: you'd think a socket is a socket, but there are differences in the designs of different manufacturers' sockets that not everybody knows about. I didn't, until I started looking closely.
The type of socket I like best is one that will apply torque only to the flat faces of a fastener, and won't round off the corners of a nut or bolt. 6-point is better than 12-point for this, and different manufacturers provide varying amounts of relief at the corners to prevent rounding. Typically the cheaper sockets are more likely to strip your nuts.
Deep sockets are funny... most of the time, what I want is a socket that is
long but also
shallow. That is, I want the hexagonal broaching at the business end to extend not much further into the body of the socket than the thickness of a nut. This allows me to load up a socket with a nut and then use the internal shoulder to push it onto a waiting bolt or screw, rather than having it slide all the way to the bottom. I think everyone has at some point experienced the hassle of having to put a bunch of extra nuts into a deep socket to get threads to engage; a "long but shallow" socket helps prevent this. Counterintuitively, it's been my experience that shallow broaching is generally found in more expensive socket sets.
Here's an illustrated example - identical bolts, two different brands of deep socket:
Having said that, deep sockets that are broached all the way to the base have their purposes (example: threading a nut onto a stud or threaded rod) which is why I keep a basic set of "long and deep" sockets around.
Given the relatively small / low-torque fasteners used throughout 95% of our airplanes, you're not likely to break a socket from overstress - unless you get a random bad one or you're trying to use that free socket left over from when you assembled that Ikea bed frame. Still, if you're buying a complete socket set that includes larger sizes, you might feel better about the future health of your knuckles if you get a set that will stand up to abuse from a breaker bar when you're working on your tractor.
Material strength is hard for we consumers to evaluate, so I tend to use country of manufacture as a
rough proxy for quality. Where a tool is manufactured may also be important to you for personal reasons. There are certain countries from which I personally try to avoid purchasing tools, unless I can't avoid it or I need something disposable (see above).
Again, speaking very broadly and from my own personal experience: I've found that Taiwanese-made tools are generally quite good and an excellent value for the money. In terms of sockets, this includes Tekton, Gearwrench, I believe some Matco sub-brands, and plenty of others.
I haven't checked recently, but I believe SK Tools still has some US manufacturing, despite being Chinese-owned at the corporate level. The local industrial tool supply place carries SK sockets and they seem pretty decent.
You can imagine there are more brand names than there are actual factories. Many tool brands are part of a larger conglomerate, for example Apex Tool Group. Something to consider when tool shopping, if it matters to you personally.
The Craftsman tools you remember from the Sears days were mostly manufactured in the US, usually by Western Forge. Their sockets were pretty basic, but if you're at a garage sale and you find a complete set of US-made Craftsman 6-point sockets for a good price, it would be hard to find a better value for money.
The current Craftsman label now belongs to an imported "zombie brand" - I have found their tools to be roughly equivalent to Harbor Freight, and treat them as such.
As for what I use... my socket drawer is mostly full of Gearwrench products, primarily because I found a great deal on several complete sets. They have a good internal profile, and the deep sockets have shallow broaching. The sets I have also include a third "medium length" that's halfway between shallow and deep, which comes in handy sometimes. The included ratchet handles are also pretty decent, although I typically reach for one of my Snap-on ones (nothing beats a good ratchet handle). I also keep around a small set of US-made Craftsman sockets that I've had forever, since the deep/deep profile is occasionally useful.
All the above is based on my personal experience and preferences - your mileage may vary. Buy tools that do what you want and provide appropriate value for your needs!