I'm a keyboardist who bought a Chapman Stick last November. I don't play it regularly outside my home since I'm still just learning. There is a guy in Denmark (I think) who plays Stick regularly at his church (http://www.youtube.com/watch?v=zsXxJNWNlxs). He plays it like a piano, not just a bass instrument. My plan is to do the same.
A Stick really does sit in the ground between the full range of guitar type instruments (including bass guitar) and keyboards. It makes sense - after all, a piano is no more than a mechanical arrangement of strings and hammers, so could be seen as a "touch-style" instrument where you sacrifice direct contact with the strings and lots of control over nuances like playing the same note in different positions for the ability to play all sorts of combinations of intervals with relative ease (I can't remember the tuning of a stick - if, as I think, it consists of 4ths and 5ths - it will become more of a finger twister as your chords diverge further from two stacks of those sets of intervals).
It looks like a demanding instrument but will be great if you can get it under your fingers.
I use a consort bass Viola da Gamba sometimes. (usually when I can find another bass player)
7 strings and frets - looks like a small string bass. (Very wide neck) I can do chords on it as the tuning is similar to a 7 string guitar (a step lower) It is bowed or strummed.
Oh I forgot to say that last summer I broke my left arm (tripped and fell in a parking lot) so I downloaded GarageBand on my iPad and played bass from it for a couple of months while my arm was immobile.