I'm just starting up in London. Cambridge sounds like a good option. Are living costs really much cheaper?

No, not really.

care to elaborate?

Sure, like-for-like Cambridge is more expensive, particular when you factor location in.

Nice place and people but awful weather IMHO. I'm rather partial to the warmer climes.

I've heard the traffic is a hassle there? Can you comment?

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.

where do you work? :)

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.