I, too, have had a few instruments. The band I am playing the most (and have been since 1990's) has seen fours, fives, and fretlesses. Even two double basses. Last three, four years I have been thinking that I have found my sound.
Well, a month ago we decided to play standards. I suggested that I could play few songs with my old EUB. Now they just want THAT, and asked me to leave my electric bass at home: "That's The Sound."
OK, fine, I think it is about playing style and certainly the sound is different. I am still a bit unsure whether I can play all the stuff only with upright (from Motown to RATM), but at least my bandmates have found "my sound".