As for EasySocial, it is a new product and the documentation is still a little spare, but you probably won't need it (just drop StackIdeas a quick email if you do). I used the the other big social engine for many years and never really got it to work correctly. I had EasySocial installed and customized to my site within a hour. The only negative is that there are not as many third-party plugins available yet (like calendars, quizzes, etc.) so be sure to consider if you need any of those to be integrated with your social flow. Even then, you should definitely try EasySocial before any other social extension - I think the support and ease-of-use will far outweigh any other consideration.
But, what I like best about this product is the wonderful support team. I've had 3 opportunities to use them over the last few years. Every time the response was quick (a few hours to overnight) and fixed the problem without any complaint or complication. This is not a commercial site so I don't have much funding but still have a critical need to keep the site operating correctly. I've never had to worry about JoomlaQuiz as I know JoomPlace will fix anything that comes up promptly. That peice of mind is worth far more than what I paid for this excellent extension!
After struggling for months with server directives, JS/CSS compressors, image optimizers, upgraded host accounts, and caching I was still left with sites that were slow, at least relative to the expectations of my impatient users. And, thru it all, I've had to deal with lots of broken links, reinstallation of corrupted sites, and those notorious Joomla invalid token errors (I even got one here on Joomla trying to write this review!)
At wits end, I took a chance on JomCDN and it immediately cut my homepage load time from around 4.5 seconds to around 2.5 seconds. Two seconds makes a tremendous difference in terms of whether a person will stay on your site or move on to the next Google hit! With additional tweaking, I've gotten the site down to the one second range, almost as fast as Google or Yahoo's home page! Who says Joomla can't be used for professional-quality sites!!!
JomCDN setup is relatively easy and there are some good videos to help. Just be sure to follow the directions explicitly. For example, JomCDN needs to be the last system extension to load. You have to turn-on Joomla's cache (and not make my mistake of turning it off later). You need to setup a cron. And, of course, you need to setup Amazon S3 and CloudFront (I think it supports other CDNs but why bother, Amazon S3+Cloudfront is extremely good and it's very inexpensive. If you are on a shared host, consider moving your whole site to the cloud!) Finally, it takes awhile for all the files and graphics to get smushed and uploaded to the CDN.
Also, I can say the support staff are excellent. I made a stupid mistake of forgetting to turn the Joomla cache back on after chase down one of those annoying Invalid Token errors. Matt, the support specialist, took the time to log into my site and graciously solve the problem without pointing out it was my silly mistake. Now, that is good customer support. Especially on such an inexpensive extension.
Other than that silly mistaken, I've had no problems whatsoever with JomCDN. It just magically works, no broken links, no invalid token errors, no problems. Be sure to check your load time using YSlow or Pingdom before you start so you have a good baseline. Then, setup AWS, install JomCDN, navigate thru your site and give the cron script a little time to catch up, and then check your load speed again. I bet you will be astonished by the improvement! Yes, it's a commercial product with an annual fee, but it's small relative to the benefit you get. It might even save you from having to upgrade to a faster server/host. For a professional site, or even a site that needs to look like one, this is a must-have!