I stayed there often as a Platinum Elite and would get a 1 level upgrade. I stayed there for the first time as a Spire last January and was upgraded to a gorgeous suite! It was only for one night, so I'm not sure if it was just availability, or if they really treat Spire members special.

I'm not sure if there is a lounge per se... I was told I could go to the rooftop bar (which is nice) and was allowed to order a few appetisers off the menu. I was brought a special menu. I can't recall what the deal was with drinks... maybe one or two free.

I see lots of people talk about getting notified of an upgrade before they even arrive; I've never had that happen to me.