Not bad, not exceptional
I just got back from HP DIA, and it wasn't too bad. I am on my "Tour de HP" week, and this week included flights to and from Denver to get my AA PLT for next year (first time PLT!). I figured -- what the heck -- pay $90 (ai) for the night and get another FFN credit. My timing wasn't such that it made sense to go all the way into downtown...
Having stayed at the HP Ontario Mills, the hotel itself was fairly familiar. Upon getting to my room, I discovered only small differences, such as no thermostat unit (HP Ontario Mills has one), a fiberglass shower enclosure (more than kinda motel-ish), and a bit of a more sophisticated TV menu system (^). The airport transportation worked flawlessly, and there were options for eating/drinking nearby (really close). Wake up call came in right on time.
Overall, my stay was fine. Without the thermostat, the window unit ended up going on and off a bit more than I am used to, and that wasn't so great. Unlike my stay at Ontario Mills, I did not get any sort of recognition for being a diamond (I am not about DYKWIA), but I found the staff to be friendly and VERY helpful. I guess the staff made me positive on this hotel more than anything else about the hotel itself. I think that this is the best thing about the HP brand that I have observed over the last 6-8 months in the 2 places at which I have stayed.
My unscientific observation about the HP chain is that the hotels (subject to interpretation) are pretty much the same from a visual standpoint. Little things like the thermostat controls, fiberglass shower enclosures (vs. strange open shower enclosures), etc. make certain properties look better or worse than others. If one is looking for a fairly functional Hyatt-related property near the Denver airport, this really works out OK. If you are looking for over the top service/luxury, this may not be the place -- that may be the sheer definition of the Hyatt Place branding.