The Tokyo Bay Maihama Hotel First Resort, while a bit inconvenient of a name, was an enjoyable stay. The hotel itself was very pristine, with a gorgeous lobby and a very nice room. The location is also quite good, but is perhaps the least convenient of the hotels on the monorail line, because it's farthest from the monorail station. Walking from Maihama Station was also a bit of a trek, so it's good that they do offer free shuttle buses.
While I did enjoy my time at the hotel, there were a few issues. The service wasn't particularly great at the front desk, especially for the Disney area. The convenience store located inside of the hotel is only open until 11:00PM and is insanely overpriced. It made us wish we had purchased drinks at the station, which were far more reasonably priced. As for issues with the room itself, the sink is in an awkward position, next to the shower room, but behind a wall that doesn't go up to the ceiling. It just looked sort of cheap and clashed with the rest of the otherwise pleasant room. Also, there was no temperature setting for the AC, so you could only choose to have it on Low, Medium, or High.
Despite those issues, the value for the room was quite good, and the location is fantastic for the less expensive price relative to the other hotels in the area. I would stay at the Tokyo Bay Maihama Hotel First Resort again, though if the price were the same as other hotels in its direct vicinity, I'd probably give one of those a try instead.