Yes, I've attended conferences at the GCH. The "registration desk" you're asking about is for conference registration, NOT hotel registration. The "whole new side of the hotel" shares the same architectural style as everywhere else, just with big conference rooms. And the "yummy conference food" is indeed yummy, but pretty much the same institutional fare as you'd get at a conference at any mainstream upscale hotel.
Have fun, which I'm sure you will, but set your expectations properly. The GCH is just a hotel, after all.