Don, the bassist in my band, has a fretless bass that he does pull out on occasion, a black '70's Jazz. Not sure he'd play the pink/purple one you have, but I like the color.
Sustain is a tricky thing. I mean, you COULD build a guitar out of a slab of granite that would probably sustain for days, but I probably wouldn't like the sound of it.
When I think of sustain, one of the guitars I think of is a Les Paul Custom. The overall design and construction; the ebony board and the heavy tailpiece, produce a guitar with excellent sustain. However, I prefer guitars with a more organic feel. While my Historic R8 and G0 Pauls have excellent sustain and resonance, the attack and dynamics of the notes are noticeably different. Their true-to-vintage spec aluminum tailpieces make a big difference over the cast zinc stop bars of modern era, non-Historic, Les Pauls. I definitely prefer a solid body or semi-hollow over a jazz box arch top--I do need some sustain for my style.
With the G&L equipped with DF vibratos, I notice similar differences between the alder and ash bodied instruments. Alder has the softer attack and more dynamics; while the ash tends to sustain longer. Typically, I use these guitars interchangeably, except for ONE song that I prefer to use the alder.
I move between the Les Paul world and the Legacy world, without too much thought these days. I like having the right guitar for the song. Sometimes I want the thickness and sustain of the Les Paul; while other times the spanky tone of the Legacy, thin as it may be to some ears, simply fits the song better. I don't believe in the concept that there is one guitar out there that can do it all.
And lets not forget the amp in this situation. People don't understand why Dumbles are so sought after, but I can tell you that the deepest memory of playing a couple of Dumble amps nearly three decades ago is the incredible sustain of the amp on the CLEAN settings. That tone is as seductive as any piece of gear I've ever seen or heard, and I can easily understand why they demand such high prices.
I use Mesa amps these days, and the LEAD channels of these amps are amazing. You're never going to get that tone out of a stomp box. And with my Legacy Special and my Mark III Coliseum Head, I've hit notes that I could sustain for days, just over the edge of feedback, totally musical. The kind of note that just puts a huge smile on your face.
So, I'd say I'm good with the the sustain of the guitars I have. It's only a part of the tonal equation. And overall, I'd say I'm happy with my tone. That's a good place to be.
Bill