I heard the horror stories from the Orlando show and went in with very low expectations. However, I'm pleased to say that my friends and I had a phenomenal experience. We spent about 7 hours on the floor and did almost everything. Lines were manageable, merch prices were reasonable and getting to play Halo Reach on PC was nearly worth the admission cost on its own. Outpost Discovery is the first gaming convention I've ever been too but it's been great so far. It's definitely motivated me to look into ComicCon/Cosplay.
That being said, I wouldn't waste your time with the App. It's a buggy mess. Also, if you're going on Saturday...may the prophets guide you on your journey. I was told they sold 2500 tickets for Friday and 3500 for Saturday. (tickets are sold out) and I expect lines will be rough. Good luck.
EDIT: If you can't do everything because of lines skip the "Ring Experience". If you've ever played a Halo game you'll basically already know everything they tel...