Stayed here for 5 days on a recent business trip. Very happy with this hotel. Although it is in a small historic building, room was very large and very modern and comfortable. Had all the usual nice Kimpton touches -- the awesome minibar, free internet, nice soap & shampoo.
Location is great, on King Street in the middle of Old Town Alexandria, walking to everything. Metro was 15-min walk via King Street, or there is a free shuttle bus. Had a nice run along the Potomac.
Only drawbacks -- parking was expensive ($25 / night) and very cramped, it would be hard to get a large vehicle into the garage. Also, the lobby was always super crowded and noisy -- it didn't in any way affect sleep quality, but would not be a relaxing place to hang out.