I had a quick look to smarty and found it excellent but after reading reviews, it has come to my attention that Smarty cons are more heavier than its pros.

1. You have to learn a new language called Smarty. (Different syntax than PHP).
2. It's a language therefore it has a complier, the compiler slows down the scripts.

PHP is a templating engine itself. If you want a simple templating class(like me) then use www.phpsavant.com v2 (for now until v3 has a documentation).

It is 100% faster and easier than Smarty.