I agree, it irks me that hotels are able to clearly block off participation in a program that brings them so much revenue. There's a fantastic Bonvoy alternative (Matild Palace) not 100 yards away, not to mention the relatively well priced Four Seasons in an arguably better location. The Marriott Hotel Dorothea is also a nice new hotel in a great location and priced well.

That said, I'm currently at Parisi Udvar and it is a wonderful experience, especially if you are are partial to historic venues. If I came again wouldn't mind paying cash, since a points redemption is just over 2c/pt redemption value anyway. If you are trying to game it and only use points, they aren't going to make it easy for us.

Also- I'm in Corner Suite 309 which appears to be slightly nicer than 308 based on the upthread pictures. It has 3 large windows in the expansive bathroom and even a sliver of a Danube view (and Matild Palace). The layout also seems a bit better than x08.