A maple frettboard might be a little brighter, but could also be the other way around.
You might feel that the response, attack, are a bit faster, but not always.
In general do maple boards through out the full note a bit faster while rosewood let the notes grow out. But it is very general, almost to the level of not being worth mentioning.
Not so much anything that can be heard, it is mainly a how it feel to play, how you feel it answers you.
The faster response was my drive to mainly use maple boards. Nut I have so many guitars that prove that theory wrong that I don't believe in it anymore.
The over all difference is in how it feels, especially if the maple have finish on it.
Not much to care to much about, you get used to whatever in a couple of minutes.
The necks of the JS
and the RG are very different, much more to consider there.
feels and plays like a normal stratocaster, different radius and neck profile (thicker, but not thick, more C) than the RG.