I have two Fender MIA Fender P-Basses: one a 2005 and the other a 2006. My 2005 P is strung with GHS Bass Boomers rounds and the 2006 P has D'Addario flats. Since I began playing bass back in 1999, all my basses had been strung with rounds, so it was a feel that I was used to.
I bought my '06 P used back in September of last year and it was already strung with flats. It felt strange at first, and I wasn't too thrilled about the feel of flats. But the more I played it the more I got used to the flats. So I figured, cool, I'll leave one P strung with rounds and the other with flats, for versatility.
Now I think I might like the flats better than the rounds, as far as feel and tone. With the treble rolled back a little ways, I get a growl with the flats that sounds really nice, vs. the same setting of the treble with the rounds. Plus I like it that there is no string noise when sliding my fingers on the flats.
So I've been doing some research on flatwound strings and what bass players like and dislike about them, vs. roundwound strings. LaBella ranks up there as favorites, along with TI's. And there seems to be the opinion that it's OK to have all your basses strung with flats and none with rounds.
BTW, I'm in a cover band that plays classic rock, modern rock, along with a little bit of country. I also have a 1986 Yamaha BB300 strung with GHS Bass Boomers roundwounds, and if I switch my other P to flats, I may just keep the Yammy as is.
Opinions? Advice?