I had a quick glance through the FreeRDP site but didn't spot any immediate clues as to whether this is a true Windows-style optimised/streamed RDP implementation or a "we'll send you a constanst stream of compressed bitmap screenshots" VNC-style...
RDP on Windows is one of the few things I really miss from the Windows ecosystem. There is nothing on Mac or Linux that I've seen to date which comes even close to the near-instantanous experience of using a Windows machine over RDP.