The most spectacular advantage may be reduced competition. Microsoft-based open source is a new market, but being a Microsoft ISV is pretty cushy place to be. From here Aras looks like a bird in a gilded cage.
For me, the key here is not whether Aras sells support licenses, but whether it gets real community support, extensions to Innovator that are donated back to the community, helping Aras build its bottom line and niche. There are lots of Microsoft shops out there -- this might be a good bet.
Or it might not.[poll id=27]