I just thought dual hoses were slightly less bad because they didn't let the ambient and hot air mix in the same hose, which allows them to move air more efficiently. I don't see how pressure has anything to do with it. All air conditioners create pressure differences. Meh, I just read an article saying that's wrong. Not a well-written article, but I'll withhold my judgment on that.

All portable AC with hoses are garbage. Dual hose is only slightly better. If it costs twice as much, you're much better off buying literally any window unit that you can get to fit.

If your apartment has walls, then that's still more insulation than the hoses have. Speaking of which, if you do end up making the unfortunate choice of buying one of these, at least put some insulation on the g*****n hoses!