It seems like I have actually gotten an acknowlegement from Hilton for comments mailed to them.
It has bugged me that every single time I have submitted a compliment on service at Marriott hotels, I have gotten the same form letter with a request for me to fill out the same survey form. The form letter contains no acknowlegement of my previous comments.
They could at least come up with two versions: one that indicates positive comments have been submitted and one that responds to negative comments. The blanket response certainly gives the impression no one is even reading let alone entering the feedback into their computer system.