The prices are falling, and there is ample supply of houses for sale with fewer sales.
Unfortunately, there are many big houses, built on small lots, which is part of what makes Waltham unappealing overall as a city to buy real estate. The crowding and over development is, in my opinion, becoming a more critical issue, and the falling property values reflecting this.
Many say that Waltham is generally a more affordable city. However, can one afford to buy a house that may be worth even less in years to come, thanks to over development?
Weston, one suburb over, is very much an interesting contrast, having sustained their average home value over a million dollars. Likewise, real estate values in Concord appear still very high. These are towns that have more stringent development controls, and seem to be more protective of current property owners.
So, as markets go, I definitely would look elsewhere. But, that's not to say there aren't some decent buys in Waltham, but it may be price that ultimately will less more costly than you realized. Then again, that's only my own personal opinion, and the statistical comparisons of the adjacent towns will ultimately be the more important assessment of this city's viability in the real estate market.