not muh difference in sound. not as far as I can tell at least. the real reason to get stainless steel is because they simply last longer than regular strings because grime doesn't stay on it as easily (or at all). if you have grimey hands stainless is the way to go, so you don't have to keep replacing the regular kind.

You don't hear many guitarists say they play steel-wound strings and the availability of them is limited. I think steel came up as a solution to desperate sweaty players who ruin their strings very fast. I think there must be a trade-off of longevity versus bite or something like that.
I haven't played steel-wound strings so I can't really say if they're worse or not.

I never paid attention to the composition, but I do pay attention to brand and radius. I used to use GHS Boomers, but I kept breaking strings at all the wrong times. So I switched to D Addario's. I'm satisfied with those.

And here is the short answer.. (google is your friend)

"Nickel Plated - This string consists of nickel plated steel wraps around a steel core. The steel gives you better magnetic pull thus more volume electronically, and the nickel helps keep the steel from corroding. This is the most common type of electric string.

Pure Nickel - This string consists of nickel wraps around a steel core. Due to the pure nickel content of the wrap this string is more mellow in tone and has less output electronically. It gives that "vintage sound"

Stainless Steel - The brightest material for electric strings, and has good volume electronically. The stainless steel is not as smooth to the touch as the nickel types of strings. Stainless steel is a very hard material and combined with its rougher texture, in my opinion, causes quicker fret wear."

Good thoughts around stainless steel. I'd rather replace strings than replace frets. I think I'll stay away from stainless steel.