Read original post by Miroslav Nedyalkov at The Telerik Blogs
After one Q in CTP stage the RadGanttView control is now BETA. This means that most of the core features are already implemented and the rest of the features we are going to add are considered marginal and will not affect its internal architecture neither its API a lot. We reconsidered the public API of the data objects (IGanttTask) and did some changes which we believe will enhance the experience of the control.