We have been using ExtremeZ-IP for years to provide AFP3 which Windows server does not offer (only offers AFP2). AFP3 fully supports OSX (AFP2 does not). It's simple and easy to install. Install, turn off SFM, done, no reboot of Win server needed.
The importance of ExtremeZ-IP is even greater given the fact Microsoft removed SFM (which includes AFP2) from Windows Server 2008.
If your mixed platform environment is forced to use Windows server on the back end, do yourself and your company a favor, get ExtremeZ-IP (SMB is not any better than AFP2) so your MacOS users are fully supported.
PS, The "Auto-reconnect" feature alone is worth the price of ExtremeZ-IP