For what it is, is one of the most complete and complex library.

Of course, this is a cowbell library and the demo track here underline just the fact that is launched for April 1st, but there are more demo tracks on their page that convince more.

Pros:

• Free.
• Works with a free sampler (UVI Workstation).
• Multiple microphone positions.
• Ensemble mode with humanizing.
• Very good looking and user friendly GUI.

Cons:

• Cowbell?