EDIT: There's now a doc page on this so this question is irrelevant, also it's outdated. Read the docs not this question.
I've been toying with the SubSonic 3 code generation for a month or so now and I'm interested in getting some feedback from others on which template they use and why.
EDIT: Rob's been blogging about the different templates so I've added links to the posts
ActiveRecord - More details from Rob's blog
Pros
- Supports a popular and well understood pattern
 - Allows easy migration from version 2.2
 - Built-in testing for ActiveRecord (See Rob's answer below)
 - Implements the Repository pattern
 
Cons
- Considered heavyweight in the objects it generates
 
Simple - More details from Rob's blog
Pros
- Generates POCOS
 - Implements the Repository pattern
 
Cons
- Generates a massive single file for all classes that can make browsing the generated source a pain
 
Advanced
Pros
- Generated file structure is much neater than simple
 - Generates POCOS
 - Implements the Repository pattern
 
Cons
- ?