[Longines] Opinion, hydro or Zulu?

Hi all, I'm pretty torn for my next purchase. I don't own any price from longlines and I also don't own a GMT. Thought l'd kill two birds with the one stone and struggling to make a decision. I'm looking for a vacation watch, something I can take abroad (so GMT), something that can be casual enough for during the day by the pool and can be dressed up a bit for the evenings. I really like monochrome black dials. I love the Zulu as I feel it's a bit more unique, however doesn't have the same water resistance. I love the hydro due to the sunburst dial plus the added benefit of better water resistance but feels very similar to my no date sub. Does anyone have any thoughts that could tip me one way or the other? Also open to other suggestions!