While the negative remarks are not untrue, they are exaggerated, to my opinion. All European pianos, as the matter of fact, all non-American pianos are more sensitive to the harsh weather/humidity of North America. And Yamaha is the only maker, who seasons the wood accordingly to the weather/humidity of the regions. And it is not that hard to keep the humidity relatively stable; installing a DampChaser or buying a humidifier will do the job. Personally, I prefer the latter. Many piano dealers in the northern part of the country have humidifiers in their show rooms.
Two sources where you might deepen your research: 1) The Piano Book by Larry Fine, fourth edition. You may find it in many public libraries. BTW, the author lives in MA as well; 2) http://www.pianoworld.com/forum/ where many members are pros, and knowledgeable amateurs, including dealers, technicians and pianists, etc. They will be generous to give you advices, tho they may not agree with each other. Maybe you just need to search the old posts, which might give you enough info already.
Good luck. Sometimes, having too many choices is not a good thing.