It depends on the bass. My main bass for the past 15 or so years is a EBMM stingray 5 with maple. I picked it up used in a town that didn't have a EBMM dealer, so I didn't have the option to compare it to a similar (but with rosewood fretboard) bass... but that didn't matter to me. It was love at first sight, and every time I play it I like it more and more.
My number two bass is an unlined fretless jazz with rosewood. Again... used, nothing comparable to try it against, love at first sight... I'm happy.
Both maple and rosewood fretboards can be good, but there are also some real turds out there, both with maple and rosewood. It's all about the bass. To the whole "better" thing... the only one who can decide what is better is you.
My number two bass is an unlined fretless jazz with rosewood. Again... used, nothing comparable to try it against, love at first sight... I'm happy.
Both maple and rosewood fretboards can be good, but there are also some real turds out there, both with maple and rosewood. It's all about the bass. To the whole "better" thing... the only one who can decide what is better is you.