Well, here's my .02.
I moved to Colorado in 1976 because I did not want my children growing up in New Jersey. Colorado was a wonderful place to raise my kids - one arrived here at 6 months old and the other is a native.
No, it's not perfect and I truly dislike the growth that's occured since I got here, but as a transplant myself, it's hard to complain, eh?
None of my family lives here any more, just me. I've been retired for over four years and I thought about moving, but I love Colorado and I think I always will. I just can't imagine living anywhere else.
Gun laws (except in Denver) are pretty good. Personally, I don't like Colorado Springs very much, but I don't have a good reason. I find it can be a tough town to get around in, but that's personal preference.
You've got good advice... change your plates and don't brag on California. There is (and has always been since I've been here) a prejudice against Californians. Not individuals of course, but the idea that they come here and immediately want to "californicate" the place. In my own experience, there's some truth to it too.
That said, I arrived here with a very NJ accent and I traveled the whole state - urban and rural - and I don't remember even a single incident when a real Coloradan ever judged me for it. These are good, decent, accepting people and one of the best decisions of my life was to raise my kids and live my life among them.