For me, the main advantages of PHP are:
- its pervasiveness,
- its ease of learning,
- its ease of coding,
- its array data structure covers most of what you want to do in its domain,
- it doesn't force you to program with classes, but you can if you have to.
Its disadvantages:
- it's inconsistent: similar functions take similar parameters in different order, because of historical reasons,
- it's not so much been designed as cobbled together,
- its object-oriented aspects have been unstable until recently, so if you have to deal with old code you have to remember that.
As a web language, I like it a lot. It's the language I code most in. But for learning, there are better languages. I'd recommend Python: it's expressive, popular, clean, well-designed, has a strong OOP implementation but you can also program in other paradigms with it.
More than the language, I'd recommend a good book or resource. I don't like Java the most, but reading Learning Java, by Bruce Eckel, has made me a much better programmer, because it deals with a lot of important stuff, and it does so clearly and at a good pace for me.