So, we were lucky enough to be in a position to buy about a dozen years back and snagged the top floor of a duplex that had just been converted to condos. On the whole, great experience. Value has doubled over the last decade (which seemed to mostly be in line with the rest of Cambridge). As others have pointed out, Cambridge has low tax rates and a tremendously attractive residential exemption.

Noise can be an issue in old houses but we've always just thought of it as a part of city-living and have (mostly) been lucky enough to have neighbors who feel the same way. Maintenance is certainly a thing but I honestly sort of dig being responsible for it and take a weird amount of early-onset-old-man-pride in fixing things myself (...when possible).

Only suggestion I might have would be to possibly prioritize a 3-unit HOA over a 2-unit HOA. If you're in a 2-unit situation, you're sort of stuck really just hoping that the other unit-owner is going to be a thoughtful, reasonable neighbor. If you've got a third in the mix, chances are at least one of the two will be solid citizens. We've mostly been very lucky with the folks comprising the other half of our HOA (our current neighbors are swell) but there was a short period of time during which we were paired up with another owner who had severe struggles with mental health and that occasionally made our home life a little less than comfortable.