Eliahu C. wrote:

> How much  is it in use by current designers ?



Because there is no replacement of ISE as FPGA backend tool for Xilinx 
FPGA families prior series 7 FPGA's, ISE is still in use by fpga designs 
around Spartan-6/Virtex-6/etc and older FPGA's.

Please ask a xilinx representative  the next time you have a question 
regarding xilinx legacy tools.