I think CakePHP is one of the easiest frameworks to deploy (you literally just upload the files and modify the config file and you're up and running) and given that it's PHP there are tons of tutorials for how to "do things" with Cake. Also just about every web host in the world supports PHP out of the gate, so you won't have to install anything extra.
Other than those things, I think it comes down to preference of programming language - if you like PHP you'll probably like Cake. If you like Ruby or Python, you probably won't.
We reviewed both Cake and CI and when it came down to it, CI won us over with one of the best user guides for any language framework (PHP or otherwise).
I haven't seen what Cake is doing lately, but I have nothing but good things to say about CI.
I'd have to recommend against PHP entirely for a. PHP makes deployment easy and development hard - which one will you be doing more of?
When asking for recommendations for tools and libraries, a bit more information about what you're doing and why you're considering what you are would be helpful.
I have built web apps in PHP for 8 years now, and created a few crawlers in perl and python over the years.
I looked at Cake and Symfony and began creating sample apps, both are an improvement from building php apps without a framework but I opted for django instead.
I'm finishing a big project on cakephp 1.1, this framework is great. But if you are starting something new - go straight to cakephp 1.2
It takes some time to go throw the learning curve, but it worth it.
We determined that Code Igniter is a cleaner MVC framework, handles more requests/sec etc. http://tinyurl.com/5dcjzd has performance data.