Attendance for Katsucon was ~7000 this year; they've been growing at about 10% these last few years, and fill the Omni Shoreham without packing it like we do with 3000 at the Thunderbird. Registration was smooth - cash and credit/debit cards only, which removes the problem of bounced checks. I didn't spend a lot of time SMOFing with the staff, but they had separate spaces for what appeared to be sizable medical, security, and ops contingents, and a quality internal radio net. Fewer, but larger video rooms, one of which was showing chop socky and other Asian films; same is true of the programming, which included three "live" tracks in addition to a workshop track and a ginormous ballroom space dedicated to console gaming.
I suspect a lot of the younger fans used the Metro to get to Katsucon; there's a stop one block from the hotel. Rooms at the Omni were $99/night, IIRC, which is damned cheap for the DC area, but then the Shoreham is pretty old (built in 1929, finished in 1930) and isn't nearly as spacious as the newer - and more expensive - hotels such as the Marriott Wardman Park (was the Sheraton Park) across the street.
It was a pretty good time; got to talk briefly to bam2 who was very surprised to see me there.