I'll just throw in my two bits: I purchased VaultWiki over a month ago because it will allow me to do unify my website into a single login and layout. The new site is still in production, so I can't show it off yet, but vBulletin CMS + VaultWiki + DownloadsII basically lets me replace Wordpress, phpbb3, drupal, and several mediawiki installations into a single vBulletin-driven site.

When you import your mediawiki installation to VaultWiki it gives you options on how you want your wiki to run. You can leave all the old mediawiki code working at the cost of some server CPU-usage, or you can convert everything to BBCode to make everything run much more smoothly. It works SOOOOOO much better than any mediawiki bridges or other connections than I have tried. Plus you can set things in your forums and CMS to display wiki article titles as automatic links to the appropriate wiki article without having to code in the links yourself. An example would be if you had a wiki for cooking recipes or something and someone posted their cookie recipe, then the words eggs, flour, chocolate, etc (anything you have a wiki article for) would automatically be turned into links to the pages for those topics. It's pretty cool and keeps your readers informed.

As for the customer service, every time I post on their support forum I get a response within a day or so, and sometimes within hours or minutes.

I haven't tried out this Lite version, since I bought the product before it came out, but I definitely suggest it to anyone who is using mediawiki and wants to ditch it for something easier to use and supports a single login.