Question about Quaser - do NPRs try to invade worlds with ground forces or is it like VB6 where the only time ground combat occurred was if you were invading someone?

You could test watch SpaceMarines new series. He is playing it ATM.

Generally the Quasar version is VB6 on speed steroids. Same game but super fast - so ideal for multi-faction or long-last games. Really neat.

The management of fleets in C# is a great improvement from VB6/Quasar; so you will miss that.
Some C# stuff Kyle has also implemented in Quasar like the Prototypes. He also copied the "No Hull" Option, but you still have to build these in a shipyard, not in a factory like in C#.
As already mentioned in C# you have to do troop management on your own as you do with ship classes. Great but time consuming feature - especially replenishing after a lossy fight. In Quasar you only have to research the already given default troop types and manage them.
VB6 still had PDCs - a nice feature which I didn't miss in C# - but I never used it that much back then. It was nice to simulate troop placement on the planet with them though.

Quasar has a functioning civilian transfer system; back in VB6 that was always a bit buggy. So nice to see that it works because it is very useful. I recently in a Quasar game blew it somehow. But if it is a bug we'll find it 

This is is the list of all the feature not included on quasar:

http://aurora2.pentarch.org/index.php?topic=10666

I play quasar sometimes as I really miss the VB6 version. There are some nice little things such as Teams, Fighter squadrons, and PDCs also there are a bit more simple ground units. Yes, you are going to miss a few Aurora C# features probably, but overall I think it's worth to try.