Denver- I hated. Nothing unique to see. But have to deal with traffic. Lots of bums & not real clean.
Denver suburbs- Ft. Collins, Longmont & others- I loved them all. Nice people. Safe. Clean. ONLY downfall was far from mountains.
CO Springs- Huge potential. Things to do. Lots of good people. But lots of rift raft too. (BTW, I'm even conservative). Lots of running possibilities.
Boulder- Liked a lot. Again, I'm conservative, Boulder can be liberal. But long as they're not obnoxious about it- I'm good. Running culture stands out. Clean. None of the rift raft of CO Springs.
Woodland Park- Loved it. A gem. Smaller city that packs a huge punch. Safe, clean, people are nice w/ some spirit. Rampart Resevoir Rd has rolling hills @ 9,300 ft for fantastically challenging runs. 8,300 ft base elevation. 20 mins from big city CO Springs. ONLY downfall, is high elevation makes it a little colder.
Breckenridge, Frisco, Leadville- The very high altitude cities 9,300 to 10,400 ft). I'd rank them in this listed order. Breckinridge is a great resort town, with a great downtown & restaurants. People love being there. Frisco has the best mountain views, but not as many things to do vs Breckenridge. Leadville has altitude, nice people & nothing else. Literally zero to do. Plus, looks run down with old buildings & chipping paint.
Overall- I like CO. Sunny & many choices. My favorite cities are Boulder & Woodland Park. Breckenridge is great- but only to visit. The Denver suburbs are great, but too far from the mountains.