I am considering Smarty as my web app templating solution, and I am now concerned with its performance against plain PHP.
The Smarty site says it should be the same
here's another templating solution XSLT here are my benchmarks for one of the pages i converted (its a simple page):
// with smarty (baseline)
0.014 seconds
// with xsl/xslt-clientside
0.008 seconds
42% decrease in server stress
// with xsl/xslt-serverside
// this process would only be done if the users browser doesn't support client-side XSLT
0.016 seconds
14% increase in server stress
Its not for everyone but if performance is your main concern :)
On top of that you allow the client to cache your template.
here's an example of what I'm doing (this is one of my sites): http://pixao.com
and here's another example of it on a larger scale site: http://worldofwarcraft.com
so far i have yet to run into any show stoppers