Guys at nabble, if you check out this forum
http://tal.ki/and take ideas from them, as you see in certain areas they are steps ahead of you and in others you are ahead of them.
LoginTheir site/forum has the ability to Log in with Facebook, google, twitter, yahoo, open ID etc..
Plugins/Intergrations: Another feature nabble is badly missing...
Their forum can eaily intergrate with wordpress, google sites, yola ,drupal,joomla,weebly,blogger etc
HomepageTheir homepage is designed better with a navigation bar and some colours it looks great.
FeaturesTal.ki detects the colors of your website, the layout, and the fonts and automatically styles itself to blend it with your site.
And the CSS can fully be edited.
Also they can add widgets sort of things on the side of their forums,footer etc something needed by alot of forum users.
Cons:*they limit on your forum use unless you pay
*rip of price when you can just get vbulletin instead
*their text editor is not on nabble levels
*i doubt they take in suggestions
*their forum structure (board>category>forum) does not look professional.
So theirs some quick points, above ^^ which you can take in to mind in the future, as you see your forum is better in my opinion but theirs has more of a social side to it.