The traffic is a hassle only in the rush hour. Most tech companies here operate on flexitime specifically so their employees can avoid it, which works pretty well.

Having said that, I haven't worked anywhere else. The perspective of someone who had would be useful.

What other US cities have you considered? Boston? NYC? Seattle? Austin?

Climate would lock you out of most of those places minus Austin.

its a hassle if you drive, Cambridge is really a cycling city.