new application

well,i simply was a php coder using php4,but new to php5.
i'm willing to develop a commercial application using php.though about frameworks and considered symfony or cakephp(zend framework still going to change).
now i'm confused as to weather create my application with/without a framework? php5 is cool and the time send learning another framework with all the associated problems i can use to get better in php5.
for a commercial application,will there be any problem if i use a framework? and what about users,will there be any dislikes cause it's developed using a framework?
is it easier to use a framework or not when i plan to distribute the app? will my users face problems if i depend on a specific framework?

thanks alot