I've also been testing the 5X, but was a bit out of the office last week for all of this discussion. Still, I'd like to help out where I can. 
The H5X hardware is very compelling for the price, but does fall a bit short on the software side of things. Like @Unforgiven said, the H5X features perhaps the best iteration of EMUI yet (and actually quite a bit less-broken than EMUI 4 on the new Mate 8), but it's still EMUI. Certainly usable, but it may still frustrate you (as it does me).
So between the H5X and the N5X, I really think it comes down to your preference and budget. Coming from a Nexus, the N5X would be a logical upgrade. Solid hardware, plus a guaranteed software experience that you're already familiar with. The H5X is quite a bit cheaper, and the hardware is still quite capable, but EMUI may be a bit hard for a Nexus familiar to live with.

I'm currently using a Nexus 4 as my daily phone. And a V10 as my work phone. I am thinking about upgrading my N4 to either a Nexus 5X or an Honor 5X. Do you think the N5X is worth the extra money?
The H5X hardware is very compelling for the price, but does fall a bit short on the software side of things. Like @Unforgiven said, the H5X features perhaps the best iteration of EMUI yet (and actually quite a bit less-broken than EMUI 4 on the new Mate 8), but it's still EMUI. Certainly usable, but it may still frustrate you (as it does me).
So between the H5X and the N5X, I really think it comes down to your preference and budget. Coming from a Nexus, the N5X would be a logical upgrade. Solid hardware, plus a guaranteed software experience that you're already familiar with. The H5X is quite a bit cheaper, and the hardware is still quite capable, but EMUI may be a bit hard for a Nexus familiar to live with.