I'm sure there are some very subtle tonal differences, but I think the main difference is how it feels in your hand and which look you perfer. Maple fretboards (at least mine on my strat) are VERY smooth, rosewood fretboards have a rougher finish. It is when you are bending strings that you will notice this difference the most.

Cosmetically, the fretboards looks very different. Back in 2000 when I bought my strat, I was unaware of the difference in feel and bought one with a maple fretboard strictly because I always thought it looked cool.

Also, rosewood fretboards require some maintenance since they should be oiled preiodically so they don't dry out. Maple fretboards don't require this. Since maple is such a dense wood, the oil doens't penetrate to any significant degree. My maple fretboard is also finished, so that will prevent any oils from penetrating too.

I learned all of this when I bought my LP Faded Studio in 2011. The rosewood fretboard on it was a totally different beast from my maple fretboard on my strat and it took a long while to get used to. Not a big deal really...just something to adjust too.

Hope that helps.