I didn't expect much from these strings, thought it was a just gimmick, but I was pleasantly surprised.
I can't say much about the feel, as to me, they feel like any other acoustic strings. Offering slightly higher tension, than brass and phosphor bronze, which could be useful if you are detuning.
As far as the sound, they are a bit more punchy, could be due to the little bit extra tension. They aren't as bright as brass strings and aren't as warm as phosphor bronze, they are somewhere in between, leaning more towards brass.
If you are looking for something different I would deffinetly recommend these.