I found fretless a very natural progression after playing fretted for a few years. My first fretless, as well as my current one, are both unlined. Not by choice, just what I ended up with, but I don't really look at the neck much anymore anyway!
I played with one of these years ago, but couldn't get on with the user interface. I love individual effects, but do wish that I'd given the Boss a bit more time and effort as I think there's some great stuff hidden within.
Just put a set of these on my Jazz yesterday (45-105 set), and am so far very impressed. Will be testing them out with a couple of different bands this week, so looking forward to seeing how they get on.