We just bought a new Mini with 10.10 on it (updated to 10.10.1) and it won't list any of the computers in the Windows Workgroup.
I can however ping them by WINS name and connect using smb://EXAMPLE/share/ so WINS lookup seems to function.
However I need to be able to browse the network, and to install a windows printer. When I try and install the windows printer it shows our two workgroups as options, but none of the computers listed in them.
File sharing is turned on (both AFB and SMB) the WINS server is configured for the local Windows 2008 Server and the MacBook Pro with 10.9 works just fine and lists all the machines.