Dirty sheets, broken shower
I travel quite frequently for work. I have stayed in Hilton hotels a fair amount, although not as often as Marriott hotels. This was the worst hotel experience I can remember. I got in after midnight, and had to be up early the next morning. I got up to my room, having had a really rough travel day, and showered and shaved to be relaxed and fresh in the morning. The shower handle was loose, so that it would swing, under its own weight, to the SCALDING hot position. Once I got it warmed up, I guess the metal expanded so it didn't swing as freely, but it took some time. I was very tired at this point, so I dried off and hopped right in bed. It was only after trying to get comfortable for 10 minutes that I detected some kind of grainy/sandy type debris in the bed, and pulled back the sheets. I do not know what it was (I of course was trying not to panic about bed bugs), but in addition to the sand, I noticed several black hairs (I do not have black hair).
I pulled back the sheets on the second bed, and observed that they were also dirty. It was after 2:30am at this point, and I was already in the bed, so I decided that whatever contaminants existed had already had their way with me. I fell asleep uneasily.
The next morning, while preparing to check-out, I called down to let them know. They didn't seem overly concerned about the sheets at first (I'm sure they were dealing with check-out rush), but after I mentioned the shower being broken, they said they would send a manager up as soon as I left. That is of little comfort to me. I called the manager a few days later, who said he couldn't do anything to make up for it as I had not contacted him at the time. In their defense, I did not bring up the issues until I was leaving (but I was only there for around 6 hours).
I see from the other reviews that my experience was not typical. I am generally a forgiving type, but I will probably never stay in this particular hotel again. In the worst hotels I've stayed in, I don't think I've ever had clearly dirty sheets (maybe suspicious sheets, but not definitely dirty).
On the bright side, the Bed was comfortable (if dirty), staff was very friendly, and the iron worked pretty well (a pet peave of mine).