Ideal Screen Sharing Conditions I realise what I am about to ask could be considered impossible to answer but maybe a discussion might be helpful to other people.

I am trying to use Screen Sharing (OS X 10.7.5) to control a Windows 7 PC at a remote site which is running Ultra VNC. I keep getting 'system not responding' errors in the applications I am using on the remote PC, even though when I am onsite I never get them. It's making things pretty hard work as I'm essentially locked out of the application for anywhere between 10-30 seconds at a time. I'm pretty certain that something to do with VNC is causing the problems and have had the same when using Chicken of the VNC on my Mac as well, does anyone have some recommendations as to what to do in this scenario?
Try the TeamViewer application for remote control.

I use it daily across the ocean and across the platforms (Windows/Mac) and it works fine.

http://www.teamviewer.com/en/index.aspx