"Autodesk SketchBook Designer software is no longer available for retail purchase effective November 1, 2012. It will continue to be included in the following Autodesk Design and Creation Suites:" Nooope.
Sketchbook Designer > Manga Studio for concept art, my opinion. Especially if you have to do lots of hard surface interations. It's SBP + vector tools. I just don't understand why Autodesk priced it too high.