@twocats reminded me that I have played in a proper concert hall on a concert piano exactly once. It was a million years ago, when I was in my second year of playing (i.e., about 25 years ago). The music school where I was taking lessons had a fancy recital. I played and sang a Beatles song. I'm pretty sure it was Let it Be, but back then I had a few songs that I sang and played, so I'm not 100% sure.
Anyway, at the time, I wasn't a member of PW yet, and my home piano was a Yamaha acoustic upright. I didn't know a lot about pianos and I don't remember what the piano was. But from the photo, I'm guessing it was a Yamaha. (This was when I lived in Japan btw, so Yamaha concert grands are more common than S&S unless you are in a more urban area).
All I remember was that it was wonderful! I think think I was nervous but this was before my recital "crash and burn" that really triggered my stage fright. Plus, I was singing, and found that to be easier than solo music.
Anyway, here's the pic:

Please share if you've played in a concert hall or played an interesting piano!