Please note all the reasons I'm about to give are the reason I had at the time I quited ZF, that's like 6 months ago or so, so be aware that things may have evolved, and since this is not a rant, I won't even check if they actually changed (as I really don't give a damn). Also, I'm writing this post only because I said I'd write it, I'm not trying to convince anyone, nor am I trying to start a discussion about the pros and cons of ZF.

First, I think the Zend Framework is a bit complex. That's quite vague for a framework of that size, but let me explain. There are a lot of things to know and do before you can even think of really working on your project. Zend Framework has a lot of classes, and you better know a lot of them to get productive.

Which lead to another problem: configuration over convention. This concept is deeply rooted inside the framework, and I think it's just wrong (although I know it's a pro for some people). It forces you to know instead of just being able to guess (and I think knowing how to guess is very important for a developer), so you just can't install the framework and start working ootb, you have to read docs (well, you always have to read docs, but), you have to read A WHOLE FUCKIN LOTS OF DOCS, and god, it's boring and greatly time-consuming.

Time-consuming, because the documentation is poorly structured. I've always found it hard to find exactly what you need in the documentation. Not sure why (and that's not a point I will expand on, since this is very subjective, and most of other frameworks have equally poorly structured doc).

Now my main point: Zend Framework is nothing more than a Zend sponsored PEAR. You have no tools to ease or speed application development, no coupling between components (yet again, I know this is a pro for some people ;), no code generation, no easy database management, no task handling, etc, etc. So what's the point using a framework if he doesn't really help you developing ? Not much if you ask me (and if you're reading this, we could assume you asked).

Add to all this poorly written components (some of them don't even follow the coding standard !), stupid decisions (i18n exceptions anyone ?) and marketing-drived release policy, and there you are, one less Zend Framework enthusiast (not that it matters anyway).

So thinking about all that, there's a single word that describe exactly why I've been disappointed by ZF: expectation. Zend Framework is just not meeting my expectations, it doesn't fit my needs, that's why I switched to another framework, that, for now, I'm fully satisfied with.