I play both.
I started on guitar and then offered to help out in a woodwind school band on bass and then started realising it was a very different instrument.
If I had to stick with 1, I'd stick with bass. There is just something about it, controlling the feel of a piece of music. Being in the background a bit, but still being far more important than many non-players realise.
It's also so easy to sit in with a huge variety of music. Almost everything has a bass part of some kind. Might be piano, double bass, tuba etc etc. But there is always something to play.