Hard to answer! I removed my first quick drafts and realized that there's more to it, than just self-taught vs formal training (I'll focus on university, and leave out apprenticeship).
Being self-taught most of the time you're in the position to get stuff done. You have a more practical mindset than devs with formal training (university in particular) I think.
Devs with formal training on the other hand have a huge theoretical background, which helps to put things in context in this huge programming world. That has given me lots of headaches. Especially when some hot new tool/component/lib comes along.
Also what's beneficial in formal training is, you can take your time to understand things entirely. When you're on projects with deadlines, this is difficult.
I'm also a self taught developer, working primarily with PHP, MySQL, and some front end stuff (Angular in particular). I always felt the underlying techniques were a mystery to me (memory layout, types, compilers/interpreters), and that a formal training would have cleared the picture.
But you can learn so much by yourself in the end. And university depends on your self-motivation as well, but provides a roadmap for you (e.g. topics, languages).
Anyways I look forward to reading other answers. Nice Question!