Cardiff is the capital of Wales. It is a fantastic city. Safe, cultured, great social buzz and pretty multicultural and otherwise diverse. It has all the arty crafty, sporty stuff that you would expect from a capital city and has a vibrant music scene. Top flight shops and restaurants. Three separate unis in close proximity, and Cardiff uni is in a lovely location near to the city centre and walkable easily.
the courses are a different matter, but don’t discount Cardiff because of the size of the city. It’s smaller but mighty!