From: "Peter Bengtsson" <mail@peterbe.com>
I.e. I start with a template and most likely end up in a template.
Am I alone on using templating objects for URL-hitting objects?
Not at all. Both patterns have their place, and making code objects primary is a relatively new idiom.
What are the implications (performance, scalability in terms of feature changes, etc.) of using Python Scripts or External Method instead of templates?
Not "instead of", but rather "in control of". The idea is that once you have more than a little code in your template, you might benefit from factoring it out into a setup Script that does a bunch of logic and then passes a set of variables to the template.
Is there a paradigm shift with these promising Page Templates (see quote above)?
I think that it has more to do with the rise of Python Scripts, although part of the Page Template philosophy is to avoid embedding non-presentation logic. Cheers, Evan @ digicool