MidwesternAloha

I'd pick which project I thought would be more fruitful for future work. Though that is hard to predict at such an early stage, you have to remember that your dissertation work is only the beginning of your research

In this case, I think the interdisciplinary program will be more broadly applicable. Not sure if that's a good or a bad thing.

broadly applicable isn't what I'm talking about. You want to do be able to set your self up to investigate interesting questions for the next few decades at least.