Well, although we stayed in precisely the same villa at Reunion (which is, without question, the best kept secret in the Orlando area), my view of the Ritz-Carlton is diametrically opposed to that of Boo.
For our January 2004 trip I was sold on the Hyatt Grand Cypress. Based on the Trip Advisor reviews at the time, it was the best hotel in the Disney area (topped only by the Westin Grand Bohemian which didn't qualify due to its Downtown Orlando location). Thanks to this forum (and specifically Simon Veness) the R-C at Grande Lakes came to my attention at the crucial moment and we ended up booking it at an amazing introductory price ($173 per night). Following 3 nights in New York and prior to a stay in a private villa, we stayed at the R-C for 4 nights during a trip to celebrate my brother's 40th birthday (dh, db, ds-i-l and me). We were all blown away by the R-C. The fact that it was brand new certainly didn't detract from its appeal, but we have been back several times since (not to stay, but to dine) and it hasn't lost its sparkle. We've stayed at some top-notch hotels around the globe, but these people could teach all of them a thing or two about customer service. Disney; eat your heart out.
Norman's (the signature restaurant) is almost a match for Victoria and Albert's. We also love Fairways (the Golf Clubhouse bar and restaurant). The Vineyard Grill is surprisingly good as the 'regular' offering. As a guest of the R-C, you can also avail yourselves of the facilities of the adjacent JW Marriott. The two are connected physically via their conferencing facilities, or you can take the outside walkways. The JW Marriott has its own fine dining options (we ate at Primo) and its pool includes a lazy river.
Just to be sure we'd done the right thing, we stopped by the Hyatt Grand Cypress. In comparison it was drab, jaded and 'Convention City'. I'm a frequent user of Trip Advisor, but you have to read between the lines and trust your own judgement.
Last weekend we stayed at the new Rosen Shingle Creek. It's a fabulous resort and has that newness that I just adore. However, it still doesn't quite match the R-C. We have also visited the (newish, i.e. post R-C) Omni ChampionsGate on several occasions. Again, it is a stunning resort, but doesn't quite beat the R-C.
I love the R-C and would stay there again in a heartbeat. For my money, it tops every other hotel in the WDW area. It's a classy resort, with an amazing ambiance. Disney doesn't even come close - and I have stayed at most of Disney's Deluxes - they just 'play' at it.