We currently have a standard PPTP VPN setup here in our US office, and we
have several users who roam around and need to be able to VPN into our main

Many times our roaming users are on the other side of the world. Even
though they are on high-speed connections, they tend to get disconnected
and/or not be able to connect at all.

It's not an IP scheme issue (we fixed that) - it seems to be simply a poor
quality connection issue, probably becuase they are so far away.

When here in the US, the VPN is much more reliable.

Is there anything in particular we can do to improve the quality of our PPTP
VPN connection?

Are any particular VPN products more "forgiving" about connections from
around the world?

Thanks in advance for any help!!