Everything has limitations or disadvantages and PHP is no exception.
The following are the limitations of PHP (so be WARNED !!)
PHP is NOT 100 % pure Object Oriented scripting language.
PHP is good if your PHP code size does not exceed 3,00,000 lines.
Maintainence of PHP code greater than 3,00,000 lines becomes more difficult.
PHP will NOT give the performance of "C" or "C++" language. Because
it is scripting language and is interpreted it will be a bit slower than
the optimized "C++" programs. For top performance, you should use "C++" and
fast-CGI with database/webserver
connection pooling and use C++ compiler optimizer "-O3" options.
Zend optimizer in PHP 4 will speed up the performance of PHP to certain extent.
But note a point that PHP was designed for very Rapid Web-Application
Development tool. If it takes about 2 months to code a web application in C++,
then using PHP you can develop the same web application in about 4 days!!
And with zend optimizer, the speed of execution of PHP will be very
close to that of equivalent C++ program!!
On the other hand, PHP has lot of advantages and it's advantages outweigh it's
limitations -
You can very rapidly develop web applications in PHP as compile and link
is eliminated in PHP scripting language.
PHP applications are very stable and do not depend on the browser
technologies unlike Javascript applications which depend on browsers.
PHP will give you the freedom to select any server platform and browser does
not know that the HTML page is generated by PHP!!
PHP has excellent database conectivity to all SQL database servers.
PHP has partial support for Object oriented features
PHP has C++, Perl, Javascript like syntax features and has programs like
'ptags/ctags' to navigate the source code
PHP has Zend optimizer which speeds up the performance
PHP runs on all unixes, linux, Windows 95/NT/2000 and is more
powerful than ASP, JSP and others.
PHP has a very large user base and developer base.
WARNING: If you want 100% pure Object Oriented scripting language
than you MUST consider Python. The 'Python' is a object
oriented scripting
language from ground up. You would be using the Python Web Application server
called 'Zope' which is available at -
http://www.zope.org
and python is at
http://www.python.org
