I worked with zend quite a bit, but switched to nushpere last year for the obvious performance differences + superior support from Dmitri. There are a few things that their analysis does that would be nice to have (but only nice to have, not at all mandatory).

1. The analysis will tell you if a variable is never used (like visual studio).
2. The analysis will also warn you of things like $this->$myproperty when you should have used $this->myproperty.

small things, but useful.

-r