I think you can get elite sound at a show - Wes Philips of Stereophile (I linked earlier) heard a room and claimed it to be the best sound he ever heard. Which means anywhere including audiophile professionally set-up rooms including his own. Under show conditions and from someone who has attended a lot of them.
I was at CES 2010 and the Venetian did indeed suck compared to the older Flamingo. But the Flamingo is concrete and you can work with concrete. If you can defeat slap echo you're more than halfway home. The room layout at the Venetian was largely rubbish.
Garth - the power issues would probably be worse for low powered Single Ended amplifiers than high watt SS amps. Most SS amps do not draw a lot of power. A SET is run full on all the time and draws maximum power from the wall. Kind of like running space heater or a vacuum. SS often has standby modes.
Personally, I am not big on going to Audio Shows because aside from power supply issues, bad rooms, it's all the people blathering away in te background - the generally monotonous music of Diana Krall and Hotel California every other rooms and piss poor MP3 players from laptops dominating the music selection.
It's just not a good place to really make a lot of insights on audio gear. Audio Shows were supposed to be intended for DEALERS to decide which brands to carry in their stores and not for the public to do serious listening and buy products because room A happened to sound better than B.
I suppose I agree with Myles - the only thing is some rooms sound a lot lot better than other rooms even when they have the same disadvantages - bad room, bad, power supply, and yet they sound a lot better.
Fortunately, in Hong Kong everyday is a virtual audio show. With 20 floors of hi-fi dealers in one building and treated rooms and set-up properly you can start at the top and listen to big Focals, Wilson Audio, Cabasse, McIntosh, Nola. Walked down a fight of stairs and audition Tannoy Westminster, Vivid Giya, TAD, Classic Audio. Go down another floor and it's MBL, LEGACY, ATC, B&W, TIDAL, Khama and on it goes. A different building will have YG Acoustics, Avantgarde, LINN, KEF Blade.
Of course finding a place to live that can support those speakers is very difficult. I pay $1800 month US for a 700 square foot apartment away from the expensive area (eesh) which limited me to speakers like the Audio Note E. Simply no space to have to pull something 3 feet into the room.