What's the difference between nickel strings and stainless steel strings ? the dude at the store tells me stainless strings have more highs, but he's a pianist, so i doubt him a lot...
He is right, though Nickels usually sound more mellow in the highs. There have been some threads on this with more detailed info.
Nickel ones are also supposed to be softer i think. And they are, in my experience. I personally dont like pure steel strings, they sound too bright for me at first, and after a while they loose all brightness. Nickel coated ones keep the little brightness thay have for much longer. IME, of course.