Although we were only in Mishima for 3 nights and on;y relaly intended to use the hotel as a base from which to see some sights around Fuji-san and the Izu peninsula, we weren't very comforatble in the Hotel Massimo. Our room was tiny and although the bathroom had a frosted glass sliding door with a pulldown screen, it was essentially visible from the bed. All in all, the room was very claustrophobic.
The room was clean though and the bed was reasonably comfortable.
The breakfast wasn't too bad, although the 'western' option consisted of 1 sausage, 1 piece of ham and a portion of scrambled egg that looked appalling (the rest of the buffet part was ok: croissant, cereal, etc). If you stay here and have breakfast, ask for the Japanese option as the fish looked alright.
Best used by people not planning on spending much time here, although the price was also a little high for what it was. As a guide, our hotels in Hiroshima and Kyoto were both much cheaper and were much nicer.