Inkscape 0.91's rendering and filters have become significantly faster, and that's only one area that's been improved.
Update: there's some confusion about the status of this release - it doesn't seem to be an 'official' release yet (although the page I'm linking to suggests otherwise).
- Cairo rendering for display and PNG export
- OpenMP multithreading for all filters
- C++ code conversion
- Major improvements in the Text tool
- Measure tool
- Type design features ,
- Symbol library and support for Visio stencils
- Cross platform WMF and EMF import and export
- Improved support for Corel DRAW documents, Visio importer
- Support for real world document and page size units, e.g. millimeters
- Numerous usability improvements
- Native Windows 64-bit build
- See Notable bug fixes