PEAR vs. Zend Framework

Hello:

I'm doing a complete upgrade to an existing site. Luckily, it's well-designed and intelligently coded.

However, the code is out of date, and I would like to modernize by replacing some of the custom classes with libraries, such as PEAR or Zend.

PEAR seems like the old hotness, and Zend seems like the new hotness.

Does anybody have any practical advice about these libraries (ease of use, speed, efficiency, developer community, support, etc.), or others?

How do they rate and compare?

PEAR - http://pear.php.net/
Zend - http://framework.zend.com/

Thanks!
Blue