If you insist in playing fretless, there will come a moment in which you'll grab the fretless over any other bass, because it comes so easy and helps you in overcoming mistakes (wrong note? Just slide to the good one!). There was a period in which I was used to play only my GWB35 and my black 55-02 (both fretless). The reason I stopped the exclusive use of fretless was so... elementar: in the darkness of the pubs, I had trouble to see the lines and this annoyed me a lot!!! Ok, ok... I am a lazy guy that does not believe in the myth of the "muscle memory" !!!
To finish my b.s. oozin, Jaco (IIRC) was used to say that the fretless basically is a bass without the speed bumps. Cheers...