With the module on:
page load average was 5.55 seconds after 8 tests. Server load average was 2.9 avg. during these tests
With the module off:
page load average was 3.36 seconds after 8 tests.
Server load average was 2.8 avg. during the tests.
This is a 40% improvement which is a 2.19 second speed improvement per page.
I had the following services on in the module: FB like, Twitter, G+1, LinkedIn, FB Send. During the tests I did not notice any significant lag with these social media platform APIs. I have used the module when the the FB and Google APIs were lagging and the page loads were taking forever (like 10s of seconds) and I noticed that sometime the page content would not fully load while the apis were lagging. I had the Module set to a module position in the upper part of my page layout, above the content. I am concerned that the module is disrupting content loading when the social platform APIs lag and in general slow down the page loads.
I appreciate the developers work and hope that newer versions fix this problem. For me I have uninstalled this module and will evaluate newer versions at a later date when I have time.
I hope this info helps.