I got my first Fender J when I was 11 and had no idea that the model they pulled off the wall for me was a fretless until I had it in my hand. The sales guy asked me, "can you play fretless" and I, being a super-cool preteen, just shook him off and said, "yeah it's no big deal". And thus, I started playing fretless from pretty much day 1 of my bass career. My personal fretless J has seen a lot of modifications: new tuning heads, Fender Custom Shop Vintage Noiseless pickups, a Leo Quann Badass II Bridge upgrade, and a wiring harness upgrade. I love the way it plays; on its own it's very synth-y but through my board it can definitely get mean, especially since I play it with DR Fat Beam roundwounds. I'll never part with mine.
Actually, 3.5 stars. This is a Made in Mexico Fender bass. The fretboard and build quality are very good, and it's fairly resonant. The tuning machines could be a little better, they have some 'creep' when tuning up to pitch, but they are adequate.
But playing fretless is FUN, and the excellent neck and fretboard feel will make you a happy player. I upgraded with a Gotoh bridge and a precisely cut bone nut and it greatly improved the sustain (a good tech cutting the slots precisely is a huge help with this). I also installed Fender Super 55 pickups - this is a solid, gigging instrument now.
Go fretless, you'll be glad you did !