Macs interact well with Windows, and with CoRD the experience is a bit smoother.
A sincere thanks to everyone who used CoRD over the years, reported bugs, donated, or contributed code - Dorian CoRD: Simple RDP Remote Desktop There's also an excellent free and open source project called FreeRDP that has great protocol support for multiple platforms.
Most people will be happy with Microsoft's clients. It's easy to use, fast, and free for anyone to use or modify. CoRD was a Mac OS X remote desktop client for Microsoft Windows computers using the RDP protocol.