Hi guys - thinking about taking the dive into the fretless world - figure the only way to learn it is to play it

I currently play an Ibanez SR prestige, and love the thin neck and playability. I am considering two fretless:
the semi hollow bodied
SRH500F and the Portamento
SRF700.
Can any one comment on either? I do like the idea of having lines on the SRH500F for assistance in finger placement.
I've been using a portamento for some time. It's very versatile, and the tiny fret markers are a help if you've got to make a big jump or need to make a visual check on position, but they're not much use for the upper strings (wrong side) or the extremes of the fingerboard (parallax), so expect to use muscle memory and ears most of the time. Pity they didn't put the markers on both sides of the fingerboard really.
The "wings" of the body are very soft mahogany which, on mine at any rate, bruise very easily. The up side of this is that the body seems to work almost like a semi-acoustic. Not sure if this is accidental or deliberate, but it's very effective.
I can't get it to sound exactly like an upright, but it's reasonably close. I've tried several different types of strings on it, from the original chromes to rounds and most recently La Bella Gold White, which are probably closest to an upright so far.
The piezo eats batteries, but if they go in mid-gig there's enough left to finish the set using the magnetic pickups. If this is important to you, the SRH relies completely on the piezo so you may not have the same security blanket.
I do find it difficult to control volume. Don't know whether mine is incorrectly wired, but the magnetic p.u. Volume controls need a lot of turning, good for subtle mixing but a pain if you're using both and need to change volume quickly. You'll also lose any mix that you've sorted out (like on a Jazz), so a volume pedal is a really good move, or just use one p.u. and change tone with the e.q. Of course you also lose any mix combination if you change from magnetic to piezo, and have to potentially alter 3 volume controls at a time - not a problem, but something to bear in mind if you're going to be in a hurry to change sound.
If you change string types you may need to adjust the sensitivity of the piezo to bring it into line with the magnetic p.u.'s. but at least you have the facility to do that.
Mine's a 5 string so there may be less neck dive on a 4 string. It's not a big problem but it is there, more so than on some of my other (asmittedly more expensive) basses.
My only other comment is that the fingerboard ends were quite sharp on mine, and I ended up running a file round to smooth them off. But all in all it's an excellent piece of kit for its price point, and it certainly draws attention with its spectacular looks.
Hope this helps.