It would seem that the official view from Google regarding the use of Geo Meta Tags, is that there is no major benefit to be gained, in terms of Web Page Optimisation.
Google’s Matt Cutts has posted a video discussing this topic and states that Google attaches very little importance to assigning country association Geo Meta Tags, to your website.
You can watch Matt’s video below.
Geo Meta Tags are recognised meta tag elements that provide information on your website’s location and country.
According to Matt, there are more established elements Google can use to determine the home country of your website, including your IP address, top-level domain and association in Google Webmaster Tools.
An excellent tip, if you have different content (on subdomains for example), is that you can specify each of these in Google Webmaster Tools, and assign country associations to each specific page. This can be very handy if your website is available in multiple languages for example.