This is one of the most comprehensive add-ons for geolocation out there. The various levels that it allows for configuration is unmatched.
However, it doesn't serve the purpose. For one, it says it allows you to configure per site but the icon that allows it is always disabled. It's not clickable no matter what option you choose. Moreover, albeit not much of an issue, it it embedded deep into page actions.
It also annoys me when it doesn't allow you to cache the location for infinite duration. I don't understand why deny the possibility if a user wants it.
Also, something that maynot be in it's purview is that a JS request as simple as one for system.time can help a website determine your geo-location.
Lastly, it doesn't work always. Websites such as iplocation.net can still determine your geo-location even when you have faked it using location guard.
I have used location guard in conjunction with and without other vpns but it has failed to do it's job consistently.
Don't get me wrong, faking geo location is a tough thing to do and this add-on does a job much better than any other, but it is still just not enough.