As mentioned in other reviews, Adachi is not connected to the main Yamanote loop that connects all the main train stations in Tokyo and staying here means "commuting" into Tokyo proper every day.
This is not that big of a deal since the Nippori-Toneri Liner runs just as smoothly and often as the regular trains, but it does mean an extra 480 yen per day (240 yen per trip if you get off at Nishi-Nippori) in transport costs. The last train home also leaves from Nippori at just after midnight, too, so if you're staying out late you're gonna have trouble getting back. (Just a small tip there - if you book a karaoke room after 23:00 at most places you get the room for the entire night, not a bad way to secure a place to hang out until the trains start running again at 5 in the morning. One place in Akihabara even provides you with a blanket and pillow.)