When comparing Udacity vs SoloLearn, the Slant community recommends Udacity for most people. In the question“What are the best websites to learn to code?” Udacity is ranked 4th while SoloLearn is ranked 21st.
Ranked in these QuestionsQuestion Ranking
Pro Courses taught by industry professionals
Pro All courses are self-paced
Courses are always made available which means there is no waiting for the specific course you want to run. You can work through the courses as fast or as slow as you want.
Pro Offers Nanodegrees
Udacity offers a few different Nanodegrees which provide access to various different courses, project reviews and coaching support for $200/month.
Current options include Front End Web Developer, Data Analyst and Android Developer. See the full list here.
Pro Courses are easy to understand
Pro Actual feedback on coding projects
You get actual feedback from developers on your code, which is useful. Yes having your sites/apps do what it is supposed to do is important, but you need feedback to learn industry standards/best practices and other gotchas that are much harder to learn on your own.
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
XP, levels, badges, certificates, etc.
Con Nanodegrees are expensive
Udacity is quite expensive at $200/month if you want to do a nanodegree.
Con Only the most commonly used languages are covered.
Con Limited usefulness for intermediate or experienced programmers
No advanced coding challenges. Look for those on other sites like hackerrank.