I've had one for a few months and absolutely love it. It's a wonderful bass on which to work out your fretless technique and intonation without spending a lot of money, if you grew up on a fretted like I did.
Get your hands on one and play it before you buy it, as others have suggested. It has some characteristics that many players, especially those who are specific about how they want their basses to "feel", don't care for.
It's a very short-scale instrument, with a pretty narrow neck. That and the responsive strings make it a very "fast" bass. I can do runs on the Ashbory that are still way out of my league on my 34" scale fretted OLP.
The silicone strings are very easy on the hands. Your hard-earned callouses might actually deter the sensitive intonation those thick strings require. They do take some getting used to, but I've found now that I've acclimated I can switch back and forth from my OLP to the Ashbory without any trouble.
That said, be sure to invest in some Slyde-Ryte silicone powder (better than talc), and buy an extra set of strings. I've not had one pop yet, but enough folks have (as another poster has noted) that it's a known issue.
Also, you'll probably want a new Fender Ashbory instead of looking for an old Guild - the instrument has been improved quite a lot by the newer tuning pegs.
Don't expect to do any slapping on it, except in the sense that you might with a doghouse bass. It takes hammer-ons and pull-offs quite well, with the slight stickiness of the strings adding a bit of punch to pull-offs, and their sponginess and the plastic fretboard muting hammer-ons to some degree.
It has a warm tone with a rich "mwah", mostly neutral, with a bit of boom on the bottom. The trebles are quite nice and crisp. Attack and decay characteristics are similar enough to an upright for most applications with the proper EQ settings on your amp. Sustain is virtually nonexistent, though, with a rapid rolloff on release.
If you like effects, it's an outstanding instrument to use as an input device.
The piezo pickups are built directly into the bridge, and the body is one solid piece of plastic. Forget saddle and truss rod adjustments. Most of this bass is in the electronics, and all of your tone modification will be done on the other side of the patch cord. If you're a tweaker, you might not care for the lack of options in that respect.
I find that it seems to play better slung high (I play "typewriter" fingerstyle), so I made a slight modification to the strap buttons (see largesound.com) and put on a mandolin strap. It weighs so little that without the strap mod you end up with "neck-dive".
Overall, a unique sounding instrument, quite inexpensive, and sure to turn heads at the gig. Some won't be able to get over the fact that it looks like a toy, but I think they look and play great.