I've used 105 Chromes on my P-bass for the past 5 years or so...
At first they are very bright and I would have to turn my tone knob down a lot, but they get to be very warm sounding to me. As others have said, they don't have as much thump to them.
The first set I had on for over 3 years, I'm on the 2nd set now. I put the old ones on a Michael Kelly ABG and they made the bass sound very nice, and PLAYABLE.
I probably won't change the Chromes on my P for a long time, BUT... After MUCH uncertainty and hesitation I finally picked up a set of LaBella 760FL flats for my 70's Jazz.... I absolutely LOVE them. I was really worried that they would be too low tension and be a little too mellow, but I'm REALLY glad I decided to go with them. They sound AWESOME on my J-bass! The tension is great for me, and I like a tighter string. Aside from the beautiful tone they have to be the most balanced sounding(from string to string) I've ever used.
I still like the Chromes on my P, but I may be switching to LaBella's on that one as well after I see how they settle in.
But off the bat, I was very pleasantly surprised at how nice the LaBella's sound and feel.
So I like the Chromes, but the LaBella's really made my J-bass come alive, and they haven't even really broken in yet.
If you use a pick, I might suggest going with the Chromes...
The Chromes are also cheaper, and I ALMOST went with what I was familiar with, but I'm really glad I put down the extra for the LaBella's.