You can now also follow other users and see their solutions... not always idiomatic (esp with the code golfers) but it still gives great insight to different ways to solve problems. Also, its not just for beginners, there are some genuinely hard problems on there.
- It starts very gentle but progresses quite rapidly.
- The problems are small and geared towards idiomatic functional programming, which is why I found it more useful than projecteuler for learning Clojure.
- There's also a neat code golf/comparison feature, so you can compare your solutions to others.