This is the perfect online learning platform I have found so far. Its easy to use. And the best thing in my experience: most of the courses on Udemy are more practical than other online learning sources. If you like something short, to the point, you will like the lessons on Udemy. But if you like learning theory, I suggest you go elsewhere.
Another thing, before you purchase a course, you should make sure to watch the free preview videos. Some teachers on Udemy, although they are great, they dont speak English as their native language. Make sure you can understand your teachers before you really purchase his/her course.
A tip for saving money on Udemy: purchase their courses in a sale season, like Black Friday, Christmas. Yearly, Udemy will have a time that they selling all courses for around$10. I usually purchase all the courses I need one time in a year only.