This software is quite useful for me, who as soon as I started taking my MacBook to work noticed that I had to manually change my network to get access to through the proxy at work. I don’t generally have any particular USB device plugged in to my computer at any specific location so I use the IP rules to change location. I haven’t had a problem with it at all. I had to leave the IP for work quite general (two numbers long e.g. 128.238.*) because it’s a large network, but at home I can use a fairly specific IP.
It’s great and if you run a Mac on different networks I recommend you try it so that Dave can see that it works with different parameters (and to make your network use easier of course).