I scored a room at the Columbia Club via the housing system with around 6 weeks or so to go. Prior to arriving I looked on their website and saw they were a "members only" hotel with "strict business attire dress code". I inquired here and other places and people informed me that they waived the membership and dress code for Gen Con but treated gamers badly and with disdain.
However I did not experience that at all. The staff was friendly and polite and I never had one issue with them. The bed was clean and comfortable, the room was cleaned well each day and the room was quiet. The bathroom was adequate, the hot water was hot though it took a while for the water to heat up. The hotel did seem a little "musty" though. The hotel is old and the room was not best room I've been in buy far but it was adequate and overall I would return there for Gen Con if I had too.
My experiences may be tempered by the fact that I treat a hotel room as only a place to sleep and shower, the only extended time I stay in the room is while I am asleep so I am rarely in the room. I leave around 7am each morning and do not return until mindnight to 1am. I sleep, get up and shower and leave. So my expectations may be lower than others.