Impossibly subjective judgement to make, but I will say that my idea of what is good tone (for my basses) has changed over the years. When I play fretless, I am NOT going for the old Pastorius sound I favored in my 20's. I want a big, fat, heavily scooped tone, to fit in with a drummerless jazz group. I don't have to worry about cutting through all the cymbals. When I play blues, country and rock, I go with a P-bass style tone with heavy flat strings (it's an MTD Heir active bass, but that tone is pretty easy to emulate on it). When I play jazz and Latin on fretted, I like a very hi-fi style sound, with a bright top end, scooped.
Ideally, good tone sits in the mix, but then a lot depends on the other players. If the other players are hogging the sonic spectrum, getting good tone in that context becomes much, much harder. It's why Squire with Yes sounds so horrible, to my ears. He had to cut through so much sound that he went over the top. Brilliant playing, though.