OK, I just looked at http://www.massbenchmarks.org/statedata/data/median99.pdf; Somerville has come up in the world. It's still below average income in Mass., but not nearly as much as it used to be. OTOH, there are only a few suburbs with lower income.

Generally, I'd estimate that if college students form a noticable fraction of the clientelle, it's unlikely to be "upscale".