Reddit.com: About to start learning my 1st MVC framework... What are your recommendations?

In this recent post to Reddit, a reader is starting out with his work in PHP MVC frameworks and is asking for some advice:

I've had a lot of experience using OO PHP but have so far written my own code. I'd like to dive in and finally learn to use a decent modern MVC framework (something I've been putting off for a while due to the time needed to get past the learning curve). From what I've seen the leading contenders are FuelPHP and Kohana, but I really don't know how to judge one over another.

Of course, there's suggestions for specific frameworks but there's also some comments that promote the "it depends" mentality - basic the framework choice off of what you're going to use it for. There's also a few suggestions of working on his own framework, just to learn how some of the pieces fit together.