I've tried all of the deluxes except AKL. Honestly, you will not be disappointed by any of them, in my opinion.
The Grand is and always will be my favorite. There is just something about it that I can't always put into words. When I am there, I am truly, truly taking a break from the everyday of life. There is luxury and pampering, beauty and grace, relaxation and happiness, like no other deluxe resort. My world moves at a slower pace (I know, hard to believe at a theme park resort). I can literally stop and smell the roses and be in the moment. Priceless.
I have wonderful impressions of the other deluxes as well. Yacht Club and Boardwalk Inn come closest, to me, to the feel of the Grand. The Boardwalk Inn has that same type of 'pretty' decor and lobby and I really enjoyed my stay there. Only negative for me is that all of the eating establishments are outside of the resort. Only a problem when the it's raining or cold.
Yacht Club I love. Quiet, refined and beautiful. Watched fireworks from my balcony. Gotta love those balconies. You have all of the amenities of Beach Club as well, but not the crazies of that lobby. You just can't beat the proximity to Epcot. Can't wait to go back and sit in the rocking chairs outside and watch the goings-on.
Poly...pure nostalgia for me. A real "Walt" feel. Casual and laid back. Can't beat it.
To answer your question, impressions of the other deluxes? Pretty great. You will enjoy them each and every one in their own right.
I would stay at any of the deluxes and be quite happy...Yacht Club, Contemporary, Beach Club, Boardwalk, Poly, etc., etc. The Grand Floridian just kicks it up a notch for me. Every time.