[quote name='Clarky' timestamp='1377551952' post='2188837']
chewing up the fretboard, for one
[/quote]
My US Masters fretless has been my main gigging and practicing bass for 6 years, only ever with rounds, and there is no wear that affects the sound at all. There are the fine lines across the board which appeared straight away but have hardly changed in the interim.
The board is Pau Ferro (don't know if this is meant to be harder than rosewood) and has a satin sheen similar to the neck itself, so it probably is some sort of treatment. If so, it clearly works!.
My defretted Hohner Jack had an untreated rosewood board, and I would never describe that as chewed up either. I think this is a bit of a myth, or certainly overstated, in my experience. Anyone else had the polar opposite?