What are the ups and downs of using FastCGI C++  vs.  PHP/Python/Perl to do the same job. 
Any performance or design pitfalls or using one over the other? Even your opinions are welcome. (Tell me why one or the other rocks, or one or the other sucks).
You can use FastCGI with PHP/Python/Ruby/Perl to get runtime performance that should be enough until your site grows really big. And even then, you can make architectural improvements (database tuning, caching etc) to scale even more without abandoning scripting languages. Some pretty large sites are done in PHP/Python/Ruby/Perl.
The big gain you get by using high-level languages is programmer performance. And that is what you should worry about first. It will be more important to respond quickly to feature demands from users, than to trim some milliseconds off the page response time.
FastCGI C++ vs. A Script Language (PHP/Python/Perl)