Last August I stayed four nights at the Park Lane Nishikasai. Two days visiting TDL, and two days visiting Tokyo.
I didn't want to spend the money to stay onsite. And I didn't like the idea of switching hotel rooms. The price savings are enormous as the onsite hotels are very expensive and probably would have cost about $200 per night more - although maybe this could be minimized by booking farther in advance than we were able.
Nishikasai is a neighborhood pretty close to TDL so the hotel provides a shuttle to the parks. Nishikasai also has its own metro stop, so it is easy to get into Tokyo. There are two shuttles each morning and two at night when the park closes. We made arrangements for the shuttle the night before, and there was no problem reserving our seats on the shuttle for our Thu/Fri visit.
Nishikasai is a very cute and convenient neighborhood with a lot of services such as shops, restaurants, convenience stores, markets.
Taking the shuttle to TDL is easy. The first morning though, the shuttle did not show up, so the hotel put us in taxicabs at their expense. The second morning the shuttle was there and the service was nice and fast.
Taking the shuttle back from TDL is not nearly as easy. For some reason, you have to take the JR line that circles Disney to the line which connects TDL with Tokyo, go one stop, and the shuttle meets you there. At that point we were WAAAY too tired to do anything but flop into a taxi to get back to our hotel instead of getting on the JR line. The first night it cost us about $23 to get back to the hotel and about $31 the next night. This was super convenient, even easier maybe than staying at one of the nearby hotels - this involved no walking- and still saved us plenty of money over staying closer. Overall, the hotel had great service and the room was in perfect condition.