None of the Starwood hotels in Tokyo are ideal for single night layovers and onward train connections. I usually choose the IC Strings for this purpose (located right atop Shinagawa station), but as others have pointed out, there are numerous suitable hotels. If you insist on Starwood, I would recommend heading straight to Nagoya after landing, which will be a lot cheaper than and comparable in hassle to Westin/Sheraton Tokyo.