Hey, which one is better, rosewood or maple? I've been asked this question too many times, my reply to this query would be: It's a matter of preference. Rosewood & maple posses different physical qualities, the reason they provide variation in terms of tone (if you can hear it) & feel.
Rosewood
Brazilian, Indian & Honduran- these are the 3 primary rosewood types used in guitar making. They vary in weight hence giving off different tonal properties. Let's consider the fact that all rosewood types are sturdy, durable & porous for the purpose of this discussion. Rosewood's open pores- this is the rather crucial consideration when it comes to tone. The presence of such openings in a rigid wood type allows it to manifest a degree of brightness most associated with the lower midrange. Rosewood has more warmth in this aspect.
Maple
Like its rosewood counterpart, a very sturdy wood type, hefty as well, without sporting open pores. The industry describes this wood as having a 'quick attack', very snappy top-end frequency hence accentuating clarity.
In use
With reference to fretboard application, both wood types affect tone but many of us could hardly hear this difference. This is further complicated by electronics; our pickups, effects & amplifiers simply mask off the true resonance of our instruments.
I'm sharing with you what I hear coming from guitars sporting rosewood & maple fretboards so it's not a concrete reference of a final outcome, just the product of my ears after listening to guitar tones since 1991...
Guitars with rosewood fretboards give off a very balanced tone once the bridge pickup is engaged; it's neither too bass-inclined nor too bright. I'd say that there's a tad more brightness to the tone but it's not excessive to the lower frequencies. As such, it has better chemistry with humbuckers which are not bright to begin with so the rosewood reinforces the humbucker's bass response while adding enough clarity to it all. The neck pickup gives off more warmth to the overall tone without being undefined; you'd hear a good lower midrange response without excessive top end bite. This is the staple tone for jazzers out there.
Moving on to maple, the bridge pickup has more top end definition to it, brighter than what rosewood has to offer. However, I find maple fretboards to be more rewarding for neck pickups as maple adds a more pronounced definition for single notes. Ditto chords (in clean mode, of course).
Bottom line
At the end of it all, ask yourself what you prefer coming from your guitar with those featured wood types. It's not about one wood being 'better' than the other. In fact, there's no 'better' here, strictly a personal preference. On a personal note, I find this consideration useful when choosing pickups for my guitars but it's NOT a sure formula. Duncan's JB for instance, has a strong midrange focus yet it sounds very commanding in guitars with maple fretboards when we tend to assume that there would be an overwhelming brightness.
Em... if you can't decide what's good for you... it's good to own guitars with both fretboard types. He he... :-)