I'm sorry. The point of my talk is that Sage is not a viable alternative to Mathematica, etc., for many reasons, e.g., not having a native Windows version. Porting a huge amount of deep technical software from Linux to Windows is the sort of difficult and thankless work that will not get somebody tenure in academia. I tried hard to get funding to get help on a Windows port, and Microsoft donated $30K for this effort back in 2008. However, $30K is not enough to fund such a huge project. In fact, I once met with a bunch of the revolution analytics devs, and learned they were getting millions from Microsoft just to port R to run natively on Windows. This was disturbing, because R is just one of the 100 components of Sage. In my talk, I mentioned the new grant in Europe that is funding the first ever fulltime Sage employee, and it turns out his main job so far is working on a native Windows port of Sage. Unfortunately, though he is incredibly good, he'll probably discover how daunting this project really is. (It's not a one guy for a few months sort of project... And yes, I tried very hard once to port Sage to Windows and failed.)