Really it has started over who could beat who in pitched combat and win. So far we haven't heard much from the Halo sector but have established the covenant are weaker than they appear. The UNSC hasn't been mentioned in detail. Right now the biggest debate is that Star Wars ships have biggers weapons, but that most are impractical in their usage.
Hot Points!:
The Quality and Power of Star Wars and Wh40K ships [So far only Imperial Navy]
Halo has been determined to have lost all credibility of even standing against Star Wars or WH40k.