I am refurbishing a big CMS that I have been working on for quite a number of years now. The product itself is great, but some components, the Database and translation classes for example, need urgent replacing - partly self-made as far back as 2002, grown into a bit of a chaos over time, and might have trouble surviving a security audit.

So, I've been looking closely at a number of frameworks (or, more exactly, component Libraries, as I do not intend to change the basic structure of the CMS) and ended up with liking Zend Framework the best. They offer a solid MVC model but don't force you into it, and they offer a lot of professional components that have obviously received a lot of attention (Did you know there are multiple plurals in Russian, and you can't translate them using a simple ($number == 0) or ($number > 1) switch? I didn't, but Zend_Translate can handle it. Just to illustrate the level of thorougness the library seems to have been built with.)

I am now literally at the point of no return, starting to replace key components of the system by the Zend-made ones. I'm not really having second thoughts - and I am surely not looking to incite a flame war - but before going onward, I would like to step back for a moment and look whether there is anything speaking against tying a big system closely to Zend Framework.

What I like about Zend:

• As far as I can see, very high quality code
• Extremely well documented, at least regarding introductions to how things work (Haven't had to use detailed API documentation yet)
• Backed by a company that has an interest in seeing the framework prosper
• Well received in the community, has a considerable user base
• Employs coding standards I like
• Comes with a full set of unit tests
• Feels to me like the right choice to make - or at least, one of the right choices - in terms of modern, professional PHP development.

I have been thinking about encapsulating and abstracting ZF's functionality into own classes to be able to switch frameworks more easily, but have come to the conclusion that this would not be a good idea because:

• it would be an unnecessary level of abstraction
• it could cost performance
• the big advantage of using a framework - the existence of a developer base that is familiar with its components - would partly be cancelled out

therefore, the commitment to ZF would be a deep one. Thus my question:

Is there anything substantial speaking against committing to the Zend Framework?

Do you have insider knowledge of plans of Zend Inc.'s to go evil in 2011, and make it a closed source library? Is Zend Inc. run by vampires? Are there conceptual flaws in the code base you start to notice when you've transitioned all your projects to it? Is the appearance of quality code an illusion? Does the code look good, but run terribly slow on anything below my quad-core workstation?