Kartsen and I have both taken action to make it easier to use either binding library (his, or ours)--the designs are similiar, and we've purposefully aligned a good deal in terms of interfaces & terminology.
While we've considered merging with Karsten's effort in entirety, as of this time we're continuing to innovate because binding is viewed as a core concern for us. To my knowledge, we have the most advanced bean binding implementation to date, notably because we are leveraging Spring to do it. This includes full support for fine-grained bean-based domain models, with nested/indexed/mapped properties.
Core Spring Development Team