Saw the Atlanta Braves here last June from row 4. Enjoyed the game, the stadium was at 90% capacity so the fan environment was on point. There's something about fellow Yankees fans, they just help make the game more exciting as opposed to the stadium being half empty.
Yankee Stadium is the second biggest ballpark behind Dodger stadium so you need to choose your seats carefully. I would avoid the Grandstand at all costs. I know the tickets up there are the cheapest available but if you can't afford decent seats, there is no sense in even going.

Section 230 is very affordable to the avg. fan and overlooked the entire left side of the field. We paid $175 for three seats which seems expensive but not when you live in New York where everything is expensive so the jobs pay more.
You can access these seats the easiest by entering thru Gate 2 on the left field side and then just take one of the elevators or ramps in the area to the second level. It's quick and easy. It's a small section so I don't imagine there will be a ton of available seats for 230 on secondary market websites like Ebay or Stubhub so just try to sit as close to row 1 as possible but they're all good seats. Take it from a fan who has already seen more than 50 games in the new ballpark since it's opening in 2009.

Another thing I will say about this place, it sure is able to hold and control large crowds really well. I think the extra wide concourses is the culprit there.