I believe that you would have to direct that question at them to get a honest answer. I could only make assumptions. I think it boils down to what you have been exposed to, your current level of knowledge and your tastes.
When I just started using frameworks, Codeignitor was the first one a tried. Why?
- My knowledge of the technology was not impressive and I found it impossible to understand less use giants like Zend and symfony.
- There were a lot of blog posts and reviews that boasted that codeigniter was the fastest framework and the easiest to use. For a while, it was like I discovered gold because i considered it a huge improvement over procedural php which I was accustomed to. However, after a while, my thirst for knowledge grew and eventually outgrew codeigniter (Fortunately, soon enough for me to abandon the codeigniter camp before a became a tainted fanboy).
I started looking elsewhere for something that would suite my needs. I evaluated literally over a hundred frameworks. I went as far as using frameworks written in different languages (chinese/mandarin) at one point (I was very impressed with the knowledge of the foreigners) [hellp thinphp
http://thinkphp.cn hello I-Framework
http://ifphp.cn ]. I've rolled with they ones that claimed to be the fastest :-O
http://doophp.com ... I could go on and on and on... but let us move on.
Eventually my knowledge grew in height to a point where I was able to see eye to eye with the big boys like Zend and symfony. They were good. However, they both had what a considered to be a dealbreaker for me. They were slow. So I continued by journey down framework road. It was then that I met Yii. We connected right away. The way it was so extensible, it had speed, the code was 100% beautiful OOP. I felt right at home with it. It provides the tools that help me to develop quickly especially when i've been sleeping on a project for weeks then the client ask me to show him/her something. I just tell him I'll put it up "later tonight". I then just run a crud on the database, drop in a few GridViews, ListViews, DetailViews etc and customize the hell out of those bad boys. By morning, I still have a client and a happy one at that.
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