Let's not fire up this debate again. Lines are fine. No lines are fine.
My fretless doesn't have lines for the simple reason that they annoy me.
Jaco's bass had lines.
I'm not a better bassist than Jaco. I'll bet he could have taken my unlined bass and made it talk. I'll further bet that I could have taken his lined bass and sounded like a dork.
Let's leave it at that.
Yeah, really!
I recommend getting one with lines because if you are coming from a fretted bass, it can get really frustrating really fast to keep intonated, even with lines! Ive seen many guys put it away because of this fact and go back to the fretted bass. I got a lined fretless and SO, SO, SO glad I did. And, it only helps a little, it still takes a good ear anyway.
You know what matters? The sound coming from your amp.
I ask again 
My myspace page is up to entice local people to hit me up, but not much luck yet.