I have played a lot of Fretless for the past five years. My intonation has gotten good for a player with my skill level. I can actually read without looking at my hands and stay reasonably in tune. I can say I really appreciate frets more than I did before I played so much fretless. I really appreciate the tonal quality of fretted notes in a way I did not before playing so much fretless. I will always play both fretted and fretless, but to paraphrase the great Anthony Jackson. I really appreciate what a fretted bass can do.