I used head first in college and honestly I'm not a fan of the style. It doesn't take itself seriously and I don't think the writing is necessarily high caliber. Head First is like the mcdonalds of tech books. You can be sure that each one will be ok at teaching you something about the topic but in each field, you can find the best book to teach you but it'll be by a variety of different authers.

So if you like reading and want a crash course on a bunch of frameworks, languages, etc, I'd buy the series. If you want to deep dive into something, look for the specialist author in that framework, language, etc.

That said, head first design patterns saved my bacon when I was studying for my first job out of college