I generally prefer simplicity, and a P-bass can be liberating for this reason. Rather than fuss with controls, you use hand positioning and technique, and can get a wide range of tones. And for playing in rock bands, I've relied primarily on P and J basses for years. I don't do much tone tweaking on stage at all, and frankly, my minimal tweaking isn't even necessary.
But sometimes the flexibility of a B string, multiple pickups, and active electronics really counts. I bought my G&L M-2500 for a musical theater project, and the tonal range was very useful. For example, the original Broadway cast recording included a heavy club synth bass part in one track that, inexplicably, wasn't in the keyboardists' scores or the bass book. The part went down to low C, so with the B string and bass EQ boosted, I was all over it. Can't do that with a regular P-bass.