I've had one for about 6 months or so. Really like it a lot.
The sustain is unreal. In the words of Nigel Tuffnel, "You can go out and have a bite to eat, you'll still be hearin' that one." It doesn't hurt that it is hands down the quietest bass ever. Never knew my other basses were noisy until I heard absolutely no noise, no hiss, no buzz, no hum from the Lightwave.
Harmonics are amazing. You can easily pull clear and bright tones from the first fret.
Range of tone is simply stunning. Growly, deep, round - whatever you're after. There are times that it can sound a lot like an upright in that you really hear the string, not the pickup. (In the interest of disclosure, that's going through a Demeter pre-amp and Bergantino 410 or Avatar TB153, all of which are pretty honest and uncolored.)
I won't pretend that I understand how it works, but it does. The rechargeable battery is a great addition.
As for the instrument itself, it's a very well made bass. Fit and finish is very good, neck is nice, fairly thin, and playable. I will warn you that the string spacing gets a little wide in the upper registers. I have no idea of the measurements, but it's due to the increased space needed for the individual pups in the bridge. Certainly very playable and comfortable for me, but it took a minute to get used to things fanning slightly up top.
I hadn't played one before buying it, but I do that anyway. I tend to like oddball stuff and I've found that if the theory behind the design makes sense and is well supported, the instrument rarely disappoints. However, if you'd like to fly me out to California, I will bring the bass for you to try...
Hope that helps.
Oh, just remembered, it seems to work best with tapered strings. They seem to fit the bridge better. I've been using the Markley SR2000 and like 'em fine. Chris was planning on offering his own brand of strings on the website but I don't know if that's happened yet. Also, I play 5 string and the low B is superb - tite, punchy, and clear as a very big bell.