I find it interesting that Synopsys would attempt to compete directly with Xilinx's System Generator product. The latter is to my knowledge completely endorsed and supported by The Mathworks. Something to investigate ...
The comercial tools market is usually based around "flows," which is a fancy way to say they try to bundle their offerings. While Xilinx is primarily interested in an FPGA flow, Synopsys of course would be happy to help you retarget your design to the more expensive ASIC flows as well. In addition, Synopsys offers hardware prototyping & emulation. All of which means while there's competition with Xilinx (and Altera, and Mathworks too) each vendor is focused a different use case of FPGA's.
