Yes, Egyptian dialect is very popular because Egypt has the biggest population (nearly 90 millions) of all Arabic countries. Personally, I prefer Levantine and Egyptian dialects because the first one is my dialect and the second, as I said earlier, very popular and widely spread. As for the other dialects, I don't understand them properly. Good luck!

if you learn Egyptian dialect you’ll be easily understood by most of other Arabic speakers without having to modify too much, but you might struggle a little to understand North African countries like Tunisia, Algeria and Morocco. plus, Egypt has been the biggest TV and film-producing powerhouse of the middle east for decades and one of the biggest producers of Arab music,so,you'll have access to a large base of dramas, movies and music that' will help you with your learning process. hopefully this helps :)

I'd also like to know! :-)