We have just released Aspose.Cells v18.104.22.168: http://www.aspose.com/community/files/51/file-format-components/aspose.cells/default.aspx .
In these new release, we not only add new features as usual, but also shape it's performance. Aspose.Cells aims to provide richest feature set and highest compatibility for different Excel files. In the mean time, performance is a very critical issue for our product. We make many performance testing and enhancement in v4.5.