Kohana vs. CodeIgniter

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I've been using CodeIgniter for a while, but am concerned that they are going to stick with PHP4 indefinitely. So I started reading up on Kohana. Here's what I found:

Simply put, Kohana has impressed me. The developers have taken all of the cool aspects of CodeIgniter, made them better and removed most of the suck from the lesser aspects. Don’t get me wrong, CodeIgniter isn’t leaving my toolset any time soon. ExpressionEngine 2.0 is going to be built with CodeIgniter so she still has her time and place of use. What I am saying is that any custom application work I do in the future that requires limited or no integration with ExpressionEngine will be done with Kohana. (onwired.com)

Over the past few weeks I have experienced with Kohana (former Blueflame), a very neat framework based on Codeigniter with a very nice community wrapped around it. It features one of the most sought features in every PHP framework, an ORM layer (which sadly, not even Zend provides). And the best of all, it is as fast as Codeigniter.
For a newcomer to the web programming world, Kohana is the best way to go when looking for a framework. It is fast, it is easy to learn and it comes with enough resources to get you started, and best of all: you can seamlessly integrate Zend Framework components into Kohana. Combine the speed of Kohana with the power of Zend Framework and you will find yourself in a very nice development environment that suits your needs and gives you a wealth of tools to implement your craziest ideas and at the same time provide your client a speedy application, in no time. (extraordinaire.me)

I took a day or two to look into Kohana which is basically the PHP5 only version of CodeIgniter. Kohana, being pure PHP5, has a few advantages over CodeIgniter. Here is a great reivew comparing Kohana and CodeIgniter In the review there are also a few tips on integrating the Zend Framework in with you CodeIgniter project – a much better use of the Zend Framework than building exclusively upon it.
Even though I exclusively use PHP5 and Kohana takes much better advantage of PHP5 than CodeIgniter does, I ended up sticking with CodeIgniter for the following reasons:
Better documentation (although Kohana’s is very good too)
I felt like CodeIgniter had a more secure and substantial user base
Kohana does not have any unit testing (but it is coming in the next release)
More add-ons (ignited code) for CodeIgniter adding any “missing” feature you can think of
My biggest complaint with CodeIgniter is the session handling. Session data is stored on the client side in a cookie. So you are limitted to 4kb of data. I prefer to store session data on the server side in a database. There are several add-ons for CodeIgniter that give you server side, database storage for session data. (refreshinglyblue.com)

I had a hard time deciding which of these two I use. In the end, I chose to use both. Why? Because they each have its advantages and disadvantages.
CodeIgniter is great for small to medium sized projects, especially good for legacy servers which have PHP4 installed. The fantastic user guide made coding in CI very efficient.
Kohana is probably better for larger sized projects as well as projects that need more flexible extensions. PHP5 offers better (proper) OOP support as the foundation, plus Kohana’s several better feature implementation make it a strong competitor to its predecessor.
There is no right or wrong for which framework you use, everyone has its own taste. For me, CodeIgniter’s excellent documentation and Kohana’s strict PHP5 + easy to use are the primary reasons to choose them over say, CakePHP and Symfony. That said, CakePHP, Symfony and other frameworks are all excellent choices depending on your taste and experience. On one hand I envy the Ruby community because they obviously have the de facto framework to work with, on another hand, we have more options hey? :)(beyondcoding.com)

It looks like the advantage that CodeIgniter has is it's longer history, which means a larger community, more and better documentation, and now its integration with ExpressionEngine.

But if someone comes out with an open source CMS based on Kohana, then that will give Ellis Labs a real run for their money.

EDIT:
I found one more juicy review of Kohana (by Paul Rouke):

My overall sense of that Kohana is that it probably will be the best PHP framework at some point in the future. It’s clear that what the Kohana community is building is something big and ambitious that might, one day, be the best way of rapidly developing PHP applications. But the shortcomings can’t be ignored: lack of documentation and lack of modules mean that there are other frameworks that can get the same job done faster. If you’re embarking on a long-term project and are not scared of using the code and comments as your primary documentation, Kohana is a great choice.

all your bases ar--