There is no outfield upper level at Tropicana Field which makes for good sight lines all over. Well, I guess you could call the tbt* Party Deck an outfield upper deck, though, it's a very small area. Those are bleacher seats and are the worst.
316 was above the Rays dugout which isn't as good as sitting behind home plate but it wasn't too bad. You definitely want to sit in the first six rows if at all possible because you will be climbing down to your seats rather than up any steps because of where the entrance tunnel is. The upper level seats have way too many seats, period.
You do have to worry about the cat walks if your seats are maybe in the last 10 or 15 rows of the 300 level sections but you can ensure a good viewing experience by buying seats on the lower level, they just cost more.

I would compare watching a Rays game at the Trop to watching a game in a circus tent. It's dim and gloomy with semi interested fans all over the place. It's a very fan friendly ballpark but it won't leave a lasting impression on you like Wrigley Field or Yankee Stadium will and it seems just as aged and outdated as Wrigley.