I just spent some time today getting this configured across my multiple Win7 machines and my OS/2 box.
In short, as already mentioned used the Win option for "simple" RDP connection...do not rely on the more complex authentication, versioning checks, etc.
On the OS/2 side of things I am a little curious about the following parameters...I emailed Andrey (the author) and waiting for feedback at the moment.
1) -P: use persistent bitmap caching
2) -b: force bitmap updates
3) -D: hide window manager decorations
4) -x: RDP5 experience (m[odem 28.8], b[roadband], l[an] or hex nr.)
It looks like using this properly might produce an optimized (smaller traffic, etc) experience...
