Ian is right, your lists will not have anything to do with your score in the event.
This time around we are giving a Player's Choice award in addition to other, more conventional awards. We will ask players to examine several aspects of each team they face. One of those aspects is the teams "theme". If the team has a poor theme or the lists are way cheesy and over the top, you may not get an exceptional score in that category. Again, this will have zero impact on your score in the tournament but will have (At least in part) an impact on your Player's Choice score.
Here's an example of where one of the five categories is currently. This is very much a work in progress:
Team / Army Composition
5 - Right out of the fluff. Super cool. Why didn't we think of that??
4 - Cool backstory, bro.
3 - Solid choices, fair lists, team makes sense in the Warhammer universe
2 - Slice of cheese
1 - Team with extra cheese
I would not advise building lists based on this snap-shot, work in progress, 20% of the Player's Choice score sheet.
The event is a tournament. There are a lot of teams registered with several waiting for a spot to open up. It would be a mistake to think you won't face powerful teams / lists if you remain at the top tables all day.
Like Ian said, the 40k community in our area is more or less full of good people who want enjoyable experiences playing the game they love. Come down with a positive attitude looking to have a great time and you probably will. You know that, Steve.