I was about to download log4net 1.2 beta 8, which I've been using for almost two years now, only to find that the project's been moved from SourceForge to Apache and an incubation release it out.

1.2.9 beta looks extremely impressive and I will report my comments on the subject as I become more experienced with it.

From the list of features the ones that impressed me the most are:

• The new logging contexts; NDCs was always thoroughly useful (never found any use for MDCs though) and an extensible, scoped NDC should indeed prove useful.
• PatternLayout customization; combined with the new logging contexts this seems to be an incredibly powerful tool (consider: conditional object state dumps with no little or no code overhead/clutter!)
• .NET formatting syntax. Trivial but necessary.
• Customizable levels for finer debug message granularity.
• Per-appender security contexts: 'nuff said.
• Pluggable file locking for FileAppender; I'm not readily sure where this would be useful, but I bet I'll find it before long...

I'm always impressed by open source goodness