baseline is cleaner looking, retains shape even when tightly packed and likely to withstand wear and tear better - i'd suggest that one if you travel for work frequently.. zdx has more casual weekend travel look and similar styles tend to bulge when overpacked.. general advice - olive (and i assume other alternative colors) color will look beaten up after a few years of travel while black will barely change

keep an eye on "like new" amazon warehouse items as well as costco - you can save quite a bit vs regular retail price