After scanning the existing social sharing plugins, I picked this one as it looked promising, and the button sets were decent enough. After a week of use, I'm a bit disappointed though...
First, we signed up at their site to get analytics and usage stats. Even a week later, the page says there's nothing to report yet, and that the first data will appear within 24 hours. So it seems like reporting/analytics doesn't work at all.
Also, we have tried to customize the list of sites (to show the most popular ones). It works for some button styles, while for others, it will just use whatever the plugin thinks should be displayed, and not the ones in the custom list. We also found that the facebook like doesn't work at all - it just opens a blank page with the text /* OK */
So... we'll be switching to a different plugin when time allows.