Scoring the scenarios, sportsmanship, and theme will be done just like the Adepticon scenarios / score sheets explain.
Sportsmanship is likely to result in a tie, in which case several factors will be used to break the tie. These factors include (but aren't limited to) what we hear from your opponents, anything particularly outstanding about how your team handles themselves, and your battle points.
Theme is also likely to result in a tie. The following factors will help break that tie:
Fluff - Both obvious and non-obvious fluff will be a key tie breaker. Submitting a write up only helps, especially if it's cool. Many of our previous winners have presented pretty incredible write ups.
How it looks on the table - Various Ultramarine Battle Companies fighting together is a pretty awesome theme, in my opinion. Unified, painted, cool looking armies that appear as though they should be fighting together definitely helps here.