I've had one of these little beasts for a few weeks now, so perhaps you'd be interested in some initial impressions...?
First of all, I love the fretless side. I mean, I really love it. So much so, that after a few days I seriously considered whether I should take the SRAS7 back and just go for a standard fretless, like the SRF700 or SRF705. I finally decided not to do that, but the SRF has now subsequently made it onto my GAS list.
Next, I've been attempting to play this as a single integrated instrument, rather than as having two basses available slung around my shoulder (like a doubleneck). That has been a bit challenging for me. There's a difference in the fretboard heights for the two sides, with which I have a love/hate relationship. On one hand it helps to orient you vertically as to which set of strings you're fingering, but on the other it is a bit jarring to have this "step" chunked right down the middle of the fretboard, especially when you're trying to play lines spanning both sides.
My other challenges have been mostly mental. Getting used to having a high 'G' directly above your low 'E' is a bit of a paradigm switch, and I still need time to get used to moving vertically upwards and suddenly jumping higher by a +octave in pitch. I know that this arrangement may offer some very interesting fingering possibilities though, so I want to stick with it. Since reading this thread, I may consider switching the fretted half to 'BEAD', since I'm wondering if the interaction between a low 'B' and high 'G' may lend itself to more happy accidents than with the standard low 'E'.
Relatedly, orienting my fingers to play both fretted and fretless notes simultaneously takes a bit of extra work too. Of course, to keep a note in tune on the fretless side, one has to place the fingertip exactly where the fret would be. For a fretted neck though, you finger right behind the actual fret. Combining both those into a single fingering gets a bit messy and I can get all sloppy with the pitch very easily, especially when I'm trying to hold a low pedal-tone up and down the 'E' or 'B' string and then play melodies on the fretless neck over the top of that. It's going to take more time for me to get used to that, it seems.
Finally, as much as I love the fretless' feel and sound, I'm still struggling with pulling the best tone from the fretted side. I am really NOT a big fan of that "new string" piano-wire sound (aside from when its used for slapping and popping, which I don't do a lot of, so definitely YMMV). In fact, I'm pretty certain that if I'd seen that video above before laying hands-on this bass, I never would have even picked it up in the store. Luckily, both fretted and fretless sides sound much more full than you can hear in that video. The fretted side still sounds too clanky for my tastes, so I'm working that out at the moment. The good news is that I can hear good things buried in there, so the right stuff is present. But I'd much rather pull the sound from it by changing out string types or similar measures, rather than always having to rely on outboard to get a good tone.
Anyway, sorry to go on a bit, but hope that helps.