Do what you like to do between these two as once you get into these specialties it will be difficult to get out at the present time. What do you think would be the differences in nursing if you are an RN, we did papers on these at uni. One facilitates getting to health potential and one maintains health and life quality.
As for futures you can become a NUM or manager of a facility or NP in those specialties.
I prefer rehab. this of course gives you all ages and I find it rewarding but thats subjective to each person.