Yeah but putty is not a replacement for a unix shell. At least for those like me who work only with Linux and sometimes other comercial Unix operating systems. Besides being a real PITA to setup tunnels and other features you can't pipe things through Putty.
While its possible to implement those on Windows through MSSFU/SUA (afaik not available for Windows 8 uh?) or Cygwin, its just too weird and alien to the underlying operating system.