I grew up in Florida and I decided to go to CU Coulder for my first semester of college. Maybe its because Im used to hot humid weather year round but Boulder was really underwhelming. One of the reasons I chose to go there, as one might expect of a LRCer, was because of the running scene. I transferred there in august and its real nice outside, did some nice trail runs and explored the area. By freaking late September the weather had become disgusting. Admittedly it'd be nice one day but the next it'd be cold as balls constantly sprinkling making everything wet, windy as hell, and the snow would just turn to slush on the ground. Honestly think it contributed to me having some sort of seasonal affective disorder because it was making me miserable all the time. In my honest opinion, the weather blows for a lot of the year.
As far as the running goes, everyone seems to forget Boulder is still a city. If you live anywhere close to the middle and don't wanna drive to get to your run, you are gonna be dodging cars and bikes and stopping every hundred yards for intersections. Its not some paradise where every street has groomed trails where runners have the right of way. If your like me and lived on campus the only thing close to me was the boulder creek path which is sketchy as hell when its dark (which it usually is by about 4PM every day in the later months). If you do have time to get to trails every day between 8am and 4pm when it isn't dark, good luck at finding a parking spot. After that, have fun not running on them on pretty much any winter month when they are covered in slosh mud and snow.
As far as the culture and college there goes, the "party scene" is completely underwhelming unless you are in a fraternity. I spent most of my weekend nights in my dorm room playing battlefield because I had tried so many times unsuccessfully to go out to with no luck. The culture there is pretty neat and it was cool to say I lived in Colorado, but to me never really matched the home feel of living in the south. They don't even have a chic fil a which seems almost criminal. Admittedly its probably the most gorgeous city in the US that I have yet to see, but living there truly underwhelms.