R5.0 is a complete re-write of Snarl using C# for the core back-end. This has added a whole new dimension of stability and performance increase to what was becoming a tired development platform (R4.0 was written in Visual Basic 6). In addition to the back-end improvements, the networking core and notification redirection subsystem has been completely re-written as well, with many more new features included.
R5.0 is still a Beta as it doesn’t include all the functionality R3.1 did (specifically, user-definable extensions and different display styles). If these features are important to you, you should stick with R3.1. If you’ve never used R3.1, then you’re better off going with R5.0. It’s also a Beta as we’re perfectionists and can’t stop from adding more new features… 🙂
Release 3 is no longer in development, however you can download the final version (R3.1) here.