You might want to ask the Japan forum about this (I stumbled across this thread while browsing new posts).
None of these hotels has a particularly amazing location, but if I had to pick one for general convenience to tourist spots, I would pick the Kanda one. You can go straight from Kanda Station to just about anywhere of note within 20 minutes on either the Yamanote Line, the Chuo Line or the Ginza Line, and you are also within an easy walk from the Akihabara electronics/pop culture district. Nihonbashi and Kiyosumi-Shirakawa are harder to get to, generally speaking.
If you're coming from NRT with luggage, the easiest access option for any of the three is probably to take the Limousine Bus to the Tokyo City Air Terminal (about 3000 yen) and take a cab from there (another 1000 yen or so). Without luggage, use Google Maps to get directions and do what it tells you to do...