I thought I'd throw in my two cents, even though I didn't actually stay at the Sugar Loaf concierge!
My husband & I had stayed at the Poly concierge for our 25th wedding anniversary and absolutely loved it, so the next trip we decided to try the Grand Floridian. Well, when we checked in to the lodge concierge I was soooo disappointed! On entering the building you walked right into the lounge (no great view like the Poly), and the room they showed us overlooked the marina and the other buildings - just nothing like I expected! "Aurelia" was checking us in, and could tell by my face that I was sad, so offered to go back downstairs to see if there was something different to offer us. I did mention that I was surprised that they would choose that building to use for a concierge, but a gentleman at the desk told me that from a business standpoint it made sense to take the building having trouble getting standard reservations and turning it into the concierge building because it would automatically be in demand then - something to think about! There was availability in the main building (RPC) (for more $$$ of course) so she took us over to show us what it was. It was Christmastime, so the GF lobby was beautifully decorated and knocked our socks off, then she used the special "card" in the elevator to get to the 4th floor to the room (#4305), right down the hall from the Roy Disney suite and when she opened the door and we saw the view (and heard the wolf call from the Haunted Mansion) we knew it was wonderful! She took us down one floor to the lounge and the orchestra was playing Christmas music and we could sit and look over the balastrade at all the festivities downstairs (we laughed that the Christmas tree must have had a magnet because every kid that walked in ran to the tree and fell down and rolled in pure ecstasy!) while enjoying the concierge offerings, well it was no contest. We were hooked, and changed on the spot! The only thing I didn't like was that the walls were pretty thin and we had a little "whirlwind" staying in the next room who was so hyped by both Disney and Christmas that he sounded like he was rarin' to go every second - I remember one night at 4AM being awakened from a deep sleep by a child's scream of "I HEARD SANTA ON THE ROOF!" I have read reports from other people who didn't care for RPC at all however, so I truly think a lot depends on your expectations and needs. We still LOVE the Poly concierge, and would stay there again in a minute! Remember this is JMHO! Good luck and have a great time you lucky duck!