A few things here (just to clarify)... The marketplace I built on top of the XenForo framework was actually a rewrite of one I built on top of vBulletin many years ago.
The domain/sites area of our marketplace was first rolled out in 2009. See this thread:
https://forums.digitalpoint.com/threads/digital-point-marketplace.1483704/
The digital goods part was originally just for eBooks back in 2011 (mainly because I didn't care if it didn't work well, since it was "just" eBooks... it was a test to see how it went before rolling out other digital goods categories). See this thread:
https://forums.digitalpoint.com/threads/ebook-marketplace.2225581/
When the resource manager was made live on XenForo, I was hopeful that it was going to do what I needed to do and I wouldn't have to rewrite the marketplace completely. But it become clear that for what *I* needed, the resource manager wasn't going to suit my needs, so I rewrote our vBulletin marketplace in XenForo from scratch (there is no code reuse or anything... I don't have a license for RM, nor have I seen any of it's code).
Yes, it *does* reuse many of the standard elements that are part of XenForo (tabs, sidebar, etc.), which is also true for a lot of other things I've built.
So what does it actually do that the Resource Manager doesn't?
Domains/Sites
It allows users to sell stuff directly (including auction style sales). For example a domain that is currently for sale:
https://forums.digitalpoint.com/threads/dirul-backlink-builder.2706942/ It allows users to display their Google Analytics and/or AdSense revenue via API (for things like site sales).
It has a lot of really advanced stuff... allowing bids/buys only from certain countries, pre-approved bidder list, etc.
It allows advanced filtering to help find domains for sale that you would be interested in (see the filter area here:
https://marketplace.digitalpoint.com/sites ), since there are thousands of sites/domains for sale at any given time. Even the thing that renders the site thumbnail was built internally by myself (I allow others to use it via an API if they want...
https://tools.digitalpoint.com/thumbnails ).
Digital Goods
Buyers pay for it right then and there (no need to set something up on an external site). Includes realtime payout of affiliate commissions if the seller set their product to have an affiliate payout.
Multi-tiered pricing options for sellers.
Handles support periods as well as renewal payments.
Handles branding removal sales, reseller right fees (for things like eBooks) as well as an optional "tip jar" for free stuff.
There is a branding API authors can use to check if the person installing the addon has a brand-free license, and then your installer can handle it appropriately (saves support and all that for addon authors). See this post:
http://xenforo.com/community/threads/digital-goods-marketplace.44009/page-2#post-696184
Basically I built something that I needed to sell my stuff, and just let other people use it as well...