I just installed a temporary M0n0wall (Using the CD and floppy) on a  
dual nic PC as a client's VPN went down and they needed a quick VPN  
solution for their network.

About 5 - 7 users might access the VPN at any one time, but  
otherwise, all the other Internet traffic from the internal LAN goes  
over another router.

I've had complaints that the VPN is slow when they access their  
network from their homes and try to run remote desktop over the VPN.

Is there something I should be aware of that might be causing this  
slowness?  I haven't really done anything over the basic install and  
then turning on VPN and opening the correct ports for that.

I've used M0n0wall on other client networks for VPN and I've never  
had reports of slowness.

Their access looks something like this:
<VPN Client at home> ====>  <M0n0wall auth'ing VPN client>  ====>   
<RDP to internal Server>

Jimmy