Hilton has locations in Vegas. I doubt you will ever see that with Hilton.
Vastly different types of resorts. Different locations. Hilton has a lot of resorts, not just a few. Disney loves to build at Disney World and Disneyland, with a few other areas thrown in for supposed variety, like Hilton Head, Oahu and Vero Beach. Are there other areas? I don't think so.
Hilton is great, but you should buy resale and not have angst about something you bought and regret. I don't know what benefits you get from Hilton developer over resale. Someone who owns Hilton could chime in on that one.
I have considered Hilton many times. There are a few locations in Vegas that have lower MF's. I wouldn't buy the Big Island, but I would buy in Vegas to book the Big Island.
Hilton is on-par with Disney when it comes to quality. I love the new Hilton on Maui in Kihei. I am hoping to exchange into that one some day. I keep waiting for it.
I think Hilton has instituted rules against renting. while Disney still hasn't cracked down on renting, as long as you aren't renting tens of thousands of points per year. In particular, we rent what we own, which is OKW. No one has said a thing. Maybe they will at some point. I did buy to use, but exchanges have worked very well.
Hilton resorts are with RCI and Disney moved back to II. That has moved some RCI exchangers to look at other possibilities for getting Disney through II. Not that much that I want has been in II lately (Disney exchanges for summer do not tempt me at all).