The most useful feature is to be able to use multiple servers in parallel, so you can have many different sites open at once without having them all slow down your computer resources or browser tabs for that matter! I wish there was more flexibility when it came to choosing which proxy server we wanted to connect too as sometimes they are not always available (or even working) but if one of our other ones works then great! We also like how easy this tool makes using proxies for research purposes - instead of manually searching through websites looking up IP addresses etc., we just click "use" button and get what we need right away.