Section 321 impressed us.
I'm always a little skeptical about upper deck seats, especially at Arrowhead since the stairs are so steep and mountainous. The Scout Investments Club seats make the upper deck seats even less desirable because they're so high up and far away from the game. The club seats though pricey are definitely worth it and will provide you with the perfect sight lines for football. Our seats were on the 15 yard line which will not be all that different of a view from the 50 yard line seats a few sections down; I've sat there for past Chiefs games. So you should feel safe about buying your tickets in 321. I guess it's all about which row makes you feel closer to the game.

Getting to the upper deck isn't all that hard. For 321, you'll want to enter walk into the stadium through the Tower Gate and then just follow the other Chiefs fans taking the escalator. When you reach the top, just follow the signage, every section is well labeled.
The $27 they charge to park your vehicle is a joke. They know they can do that because they're so far from downtown Kansas City that Chiefs fans have no choice and that Chiefs fans love to tailgate. There is also no train or subway to take fans to the game either. If you're staying at a hotel near the stadium, your best bet may be to have a cab drop you off at the stadium although it may be hard to find one on game day. (Arrowhead holds 77K).