Having experimented with dozens of strings, would have to agree with other posters that there is "nothing like it", and i keep coming back to ALU power. I like it in a full bed in the mid to high 40's for tension. (18x20). When the weather turns colder i like to hybrid it with Natural Gut at about the same tension with the gut mains 3 lbs tighter. This allows for more feel as the cold weather makes strings seem stiffer.
I am currently experimenting with 4G as cross. (this for another thread) and with some promise.