I started out with using HTML::Template, it was the first template system that I knew, and I liked it.

I then read a Catalyst tutorial, and that used TT. I really liked it, and started using TT.

My first doubts about TT came when realized that it missed a killer feature that HTML::Template had: the default_escape option. It really makes all your worries about cross-site scripting go away.

When I tried to make my web apps "Unicode Safe" I moved them from HTML::Template to HTML::Template::Compiled, which has the open_mode option to get rid of my UTF-8 worries.

I started to write more things with Catalyst, DBIx::Class and TT, and came to the conclusion that this model, while much more powerful than HTML::Template + $otherStuff, tempted me to do bad things, like issuing DB queries from within the template (if you don't know what's bad about this, just think of how you'd handle error cases).

So these days I mostly use HTML::Template::Compiled again.