Well, you can't beat the convenience of walking right out into DCA, lol. It may be just as far from the DL main gate as the Fairfield Inn (though you could take the monorail). Is it worth an extra $300? Well, to some people for sure - to me I'm more of a penny pincher, and have a hard time paying over $150 for a hotel
. It for sure is a very nice hotel, though I've only stayed in a regular hotel room (before they added on the villas). It is quite difficult to get a room there, though. There aren't many villas (relatively speaking) so they are often sold out. You can ask any member if they'd mind checking availability for you (there is an online booking engine on the member site)
Hope that helps!