I was always under the assumption there was only one class of room here and never worried about the upgrade until scoring it one day. Although in my opinion the difference is so negligible I doubt I would have even noticed if I hadn't been told at check in, from memory the only difference was the sofa and marginally higher floor/improved view like you mentioned.

I've had a number of really good stays here and in terms of preference, I rank it above the Doubletree and depending on the rate, nearly on par with the T4 Hilton.

Not sure if he's still there, but in early 2015 I stayed here quite frequently and one of the Front Office supervisors, I think his name was Kasal? began to recognize me and his service was, quite frankly, outstanding. He always warmly welcomed me back by name, made a fuss over my diamond status, frequently with things well over and above the stated benefits. On one occasion, just after checking out, I took a look at my phone and saw my flight out of T4 had been delayed quite heavily. So I asked if I could stow my bags for a few hours, Kasal replied with "Oh, why don't you just leave them in the room? I can give you back the key, how long would you like it for" happily giving me back the room for the rest of the afternoon, I think I didn't end up leaving until well after 4pm.