If you like the SF / West coast progressive vibes, Boulder will be better. Denver is bigger with more diversity and things to do. It's super easy to meet people because many are new and looking for friends. Definitely much cheaper than Boulder. Housing / rent should be going down, lots of new buildings going up.

I'm leaving CO because the air quality is so bad out here, especially in Denver. Sixth worst last time I looked.

Denver has a vibrant tech scene like Boulder and you will find they only ask for normal work hours. Work life balance is a big part of the Denver culture. People love the outdoors activities, sporting events, and drinking. This is a heavy drinking / drugging town (another reason to leave)

If Denver sounds like your preference, I can tell you more about the neighborhoods and put you in touch with an amazing apartment search company. Literally the best experience I had looking for a new flat, they did everything, scheduling viewings, Uber you around, buy lunch.