Summary

If you're working with .NET 3.5, by all means use SubSonic 3.0. If you think you're going to need to work with 2.0 ever - use 2.x.

Considerations

2.0 (and subsequent point releases) are by far the most stable codebase SubSonic has. 2.x has been in the wild for over 2 years and has reached a nice stability point.

3.0, on the other hand, is very, very new. Having been released in June of 2009, it was under development for almost a year and has undergone a lot of testing on projects and Real Life. That said, there may still be some lurking bugs in the core since a lot of it was streamlined and rewritten.

Support

Both of the libraries are supported by the community in the form of patches and contributions. SubSonic's main contributor and Chief Overlord, Rob Conery, works on bugs when he can, and loves to have people contribute patches to fix the bugs in the butter.

Pros and Cons of 3.0

3.0 uses Linq, a lot, as well as many of the C# 3.5 language features - such as Extension Methods and Expressions. If you're not comfortable with any of these, 2.x might work better for you.

If you are comfortable with them, then you can save a lot of code using the shortcuts the new features provide. A long query can be cut to 1 line using an Expression set, for example.

Whichever you choose, our goal is to get you home earlier - let us know how we're doing.