As with most things of this genre its all up to personal experiance and preferance. Both will do what you need them to do, PHP is more widley used so from a development perspective code editability (not sure if thats a word.... but sounds cool) and understandabilty (sure thats a word) from third parties prolly makes it 'better'. But as i said at the beginining Its all about personal preferance. Hope this helps.
JSP is way better than PHP but for JSP you need to have basic knowledge of JAVA whereas you can easily use php with little HTML and C language.
A major drawback of JSP is that it's much harder to find hosting for it. It may be the most awesome thing in the universe (it's not; you'll spend much more time developing with JSP) but your deployment options will be quite limited.
Depending on what you do. And jsp is not client side. JSP - Java server pages. PHP is much more popular.
You'll go around the houses on this one with people who don't really know enough about one or the other language claiming that it is the 'Because it r0X0rz'; others will stun you into silence by claiming that JSP is a client side language... Fact is they are completely different, and are used in different circumstances. Can you do the same things with them? Generally yes. Would I put together a 5-page brochure site using JSP? No. Would I embark on a huge Intranet for a multi-national company using PHP? Probably not. So, in answer to your original question, my resonse is: it depends.