My dh grew up in Denver, and we still have lots of family there.
Denver is booming and I think that housing is ridiculously overpriced, but we chose not to move back (and sold the house our in-laws left us) because I am not willing to deal with that kind of traffic. That is a big quality of life issue for me, but may not be for other people. Denver has moderately good public transit, but again - it takes forever to get places IMO. And for what it's worth, I wouldn't live in Boulder again at this point, but lots of people love it.
If you want to do stuff in the mountains, you've got to drive there, and that was always a big disincentive for me, even when the traffic wasn't bad like it is now.
Denver is a huge sprawl because it has to spread along the mountains.
Other than housing, I don't think Denver is crazy expensive (and my standards for "expensive" are quite low.) I like Colorado in general, and it's very pretty, and I'd be willing to live someplace Not Denver/Boulder, and I include Longmont in that. And I'm not nuts about Colorado Springs, either, but that's politics more than anything else.
The weather is nice - cold, but lots of sunshine. There's a lot more flooding than there used to be, because it's so overdeveloped there, but the air quality is better than it used to be.
But if you're already living in Colorado, you should go look at some places in Denver and see what's around in your price range.