Considering I live in West Arvada, I'm a little biased. On the other hand, Louisville was ranked by Money magazine as the number one place to live in the nation, and I have friends who live there. That being said, I think it's important for you to drive through the neighborhoods of both areas, at different times, different days, maybe even stop and say hello to people who are out and about and get a feel for the neighborhoods. You need to feel good about where you'll be living. Additionally you'll want to look at your commute to work, and of course, budget will need to be a consideration as well. As for schools, you can check sites such as http://www.greatschools.org (among others) to look at school ratings/rankings. Where you buy depends on what's going to work best for you, in your own, subjective view.
If you'd like more information, I'm happy to help you in your search; feel free to contact me.
Your Castle Real Estate