Good question. I think that it depends on the type of guitar.
On electric, I've always leaned toward D'Addario nickel round wounds. I've never gotten a bad string out of the package like I have with some other brands. Plus my acidic body chemistry doesn't kill them as quickly.
I used Phosphor Bronze D'Addarios on acoustic for a long time but have recently switched to John Pearse Nickel acoustic strings. They seem to keep a bright sound longer than the PB.
Plus on the reso they sound more "old time-y".