The thread would largely be in favour for the Shivans.
All the more, we're in the official forum for FreeSpace, not the forum for Halo.
So Shivans = overkill
1. We all know that the Shivans have an extremely large Empire, and that the Sathanas fleet was just a small group of armed transports.
2. Halo ships may be faster, but didn't the Shivans come to the Capella star from the jump node in just a few days? That would be tens of thousands of kilometers, so we know that the game speeds were just for balance.
3. The Haloverse never had ships that could generate a supernova - though the Halo Array was an extremely powerful weapon, it was destroyed.
4. A plasma torpedo would be like 3 Teratons, and one could easily blow up a ship. It required around 900 teratons to destroy a Sathanas (based on my calcs). Of course this is probably just fluff, but if you're going to argue fluff, then here's your fluff.