As I work with WordPress for a variety of clients this is one of the plugins I recommend to them as a necessity, especially now that Social signals are so valued in the Google algorithm.
That said I was really impressed by the fantastic customer service I got when I had a problem using this plugin. It turned out that it was not the plugin but an error I had made elsewhere. Despite that I got help fast and with courtesy - hey it was my own stupidity that resulted in the error message I got.
This plugin is a life/time saver and although the free version is great the Pro version is worth every cent I paid.