As people have said it all varies dependent on the hotel. I've been a Marriott Plat, SPG Plat and HH Diamond. Of them all I've been a HH Diamond the longest (since 03 I think) and, in my experience, there has been a steady degradation in recognition.

This week I stayed at a Doubletree and city centre Hilton, my recognition consisted of 2 bottles of water at the Doubletree and absolutely zero at the Hilton, I asked about room upgrades at both and got nowhere. On the other hand I've stayed at the Waldorf and been upgraded to a 3 bedroom suite at the Towers. Another city centre hotel I stayed at 3 weeks back had a letter from the mgr, room upgrade and bottle of wine waiting for me.

Hilton has a serious issue in consistency across the estate, especially for top tier. Unfortunately it's now more common that you have to push for some benefits than an automatic recognition. Marrriott was better and SPG was far better (in my experience the best in terms of consistent recognition of status), however Hilton have more hotels where I travel.