First off, take note that the sections along the sidelines of the upper level have the most rows so there will be a lot of steps in your path pretty much no matter where your seats are. If you have kids or an elderly friend or parent, stay away from the upper deck or sit in the first few rows. For the first ten or so rows, you'll walk down to your seats rather than up because the entrance tunnel is in the middle of the section; this goes for every section in the 300s. However, that also creates a lot of traffic after the game when everyone is heading home and trying to exit the same tunnel. (If Chiefs play like last season, fans will be gone by the start of the 4th quarter.

Even though 305 overlooks the end zone, we were always able to see the entire length of the field without difficulty. All of the seats are colored red too which gives the Chiefs a little bit of that home field advantage (sometimes).
The stadium itself is a concrete monstrosity. Even after the upgrades, it still feels dated and the same as it did back in 2003 ten years ago. The best feature of the renovations was obviously the Hall of Honor on the main level. The tailgating in lots A thru H will be epic but there are a number of NFL franchises that can compete with the Chiefs fans in that regard (Packers, Redskins, Bears).