Drupal Forum Solutions? Contemplating a new forum for a D7 site. There are many options floating around out there, and it's not very clear which of the solutions listed below would be the best direction for our use case. And which are still current (some posts and projects are quite old). Advice?

Features we're looking for:

• Has staff moderation. Volunteer moderators can be assigned.

• Private messaging between members.

• Users can earn or be given “badges” and have a nice leaderboard – we would like to use it to create an "expert" vs "new user" atmosphere for Q&amp;A threads, with new contributors asking more seasoned ones (or staff moderators) for advice

• [Advanced] A stub of the most popular discussion(s), i.e. linked title (# of replies) can be pulled into a relevant landing page, using categories or similar to define which forums belong to which landing pages. This is important to bring user generated content into landing pages. An extra bonus would be the feature of over-riding the 'most popular' discussion with another staff featured discussion at landing page level.

• Doesn't require subdomain or iframes to integrate - can reside at something like domain.com/forum/thread or domain.com/landingpage/forum/thread

• Clean and modern UI out of the box or can be themed, responsive for mobile

• Can use Drupal user authentication or replace/supplement it with OpenID or Facebook/Twitter logins

• Includes spam control, though this isn't a deal breaker.

• [Advanced] Comments can get upvotes for helpfulness

And here are the choices that seem to be out there:

1) Core forum module - probably can't do a lot of the above?

2) Advanced forum module - how much of the above can it accomplish? If it can do most, this seems like it could be the easiest option to integrate ...

3) VBulletin - some of the larger Drupal sites with really active forums use vbulletin, typically implemented as a subdomain. There's also DrupalVB https://www.drupal.org/project/drupalvb ; phpBB is also an option

4) Acquia Commons Drupal project/modules

5) Harmony Drupal project/modules

6) Discourse - https://www.drupal.org/project/discourse . New and cool, but maybe their Docker isn't easy to integrate into a complex existing Drupal site.

7) A third party konwledgebase platform like GetSatisfaction or Zendesk. These have nice UIs, a lot of the required features from above, and Drupal integration modules already exist - but integration may still be quite complex...

Ease of integration is important, but so is how full-featured the solution is. And whether it's got a nice, modern UI.
The Advanced forum module might be a good starting point, since Drupal has a modular approach you'll have to use a lot of building blocks (drupal contrib modules) to get to the extended functionality that you desire. There might be some custom code needed. In short: there is no out of the box solution for this nor a short answer to help you build this forum but here is a good start:


Has staff moderation. Volunteer moderators can be assigned. 
-> Use Workbench
Private messaging between members.
-> Use Privatemsg
Users can earn or be given “badges” and have a nice leaderboard – we would like to use it to create an "expert" vs "new user" atmosphere for Q&amp;A threads, with new contributors asking more seasoned ones (or staff moderators) for advice
-> Badge/score system might be custom, the overviews you can build with Views
[Advanced] A stub of the most popular discussion(s), i.e. linked title (# of replies) can be pulled into a relevant landing page, using categories or similar to define which forums belong to which landing pages. This is important to bring user generated content into landing pages. An extra bonus would be the feature of over-riding the 'most popular' discussion with another staff featured discussion at landing page level.
-> Probably some custom code with also views to pull the lists
Doesn't require subdomain or iframes to integrate - can reside at something like domain.com/forum/thread or domain.com/landingpage/forum/thread
-> Use PathAuto and again views for the landingpages overviews with dynamic urls
Clean and modern UI out of the box or can be themed, responsive for mobile
-> Omega's example theme Ohm might be a good starting point or you could build a child theme from scratch on omega
Can use Drupal user authentication or replace/supplement it with OpenID or Facebook/Twitter logins
-> Try OpenID connect, Facebook connect, not sure if there is something like this for twitter
Includes spam control, though this isn't a deal breaker.
-> Use Mollom or Honeypot
Comment upvoting
-> Use Vote Up/Down