When comparing SoloLearn vs CodeProject, the Slant community recommends SoloLearn for most people. In the question“What are the best websites to learn to code?” SoloLearn is ranked 17th while CodeProject is ranked 36th.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Completely free
Pro Offline learning mode for mobile apps
Allows learning while disconnected from the net.
Pro Easy for beginners
Anyone can get started with this.
Pro Share and modify others' projects
Pro Browser-based code playgrounds
No software installation needed, just a modern web browser. On mobile devices though the mobile apps are highly recommended.
Pro Excellent mobile apps available
Pro Gamification
XP, levels, badges, certificates, etc.
Pro Lounge
Relax in the lounge !
Pro Q&A forum
Friendly and supportive community, questions are answered very quickly most of the time.
Pro Quality articles
Cons
Con Only the most commonly used languages are covered.
C++, Java, JavaScript, C#, Python, SQL, PHP, Swift, Ruby, JQuery, HTML, CSS. You won't find anything less common like Haskell, Erlang, Elixir, Common Lisp, Scheme, Clojure, Rust, etc.
Con Limited usefulness for intermediate or experienced programmers
No advanced coding challenges. Look for those on other sites like hackerrank.
Con Sometimes slow
Seems a victim of it's own popularity, website can be slow when many users are logged in.