Both are excellent places to live. We looked extensively in Ellicott City before deciding on a home in Columbia. Ellicott City has lots of large single family homes in stately residential neighborhoods with all the shopping/restaurants on Route 40. The only real exception is the historic downtown, which is in an odd pocket (and has major floods—be aware). EC has a large Korean population and many Korean restaurants. Schools are top notch. Columbia has more people, is denser and has more shopping, restaurants and activities. It is a much newer city and doesn’t have the quaint downtown. It has a much wider variety of housing, so you need to look at the neighborhood level. Many schools are also top ranking. Columbia is extremely diverse. It has a phenomenal park and trail system. While EC is closer to Baltimore, southern Columbia is accessible to DC, which is great for weekend trips. Columbia is a planned community, and between the Columbia Association and Howard Hughes Corp, there is always something major being planned or built.