you have a series of unnecessary DB calls in your code, for example in /components/com_jsn/helpers/helper.php line 107ff. If you cache that DB call (it is static for every page load) you can save 20 calls on list view on my installation. While you are in the process of caching, you might wanna look into further optimizations, so that you don't have to parse the params each time, etc.
Besides that, there are two DB calls for every user that you load, which are identical. Maybe you can reduce that to one call.
Last but not least, why don't you use a factory method to create user objects like Joomla does? You could cache the user objects there in that case...
Besides that, your product is far superior to Community Builder and I'm very happy that there is finally a better solution for communities.
Regards,
Hannes
