The layout of the seats are a lot better at new Yankee Stadium than the old stadium, but the new one has a more corporate feel than old Yankee. It's full of too many of these rich Manhattan dwellers that want to sit in the private clubs and suites, than the regular Joe that wants to grab a hot dog and beer and catch the Yankees in person. The prices here are crazy which is why I go to only about 3 games a year because of that. These are far from the best seats in the ballpark but they get the job done. 427 will allow the average fan to see their beloved Yankees without completely breaking the bank.
The upper deck is also called the Grandstand and the majority of Yankee Stadium's capacity is focused on this level. So there will be a lot of rows to climb thru to find your seats in 427. Stay out of any row that's in the 20s as those are usually too high up and the famous "Façade" will probably be in the top portion of your line of sight.
The Terrace seats are much better if you want my opinion but those seats are a little more expensive but oh so worth it.

There are ramps on the bottom level that lead to all levels of the ballpark so make sure you arrive to the ballpark 30 minutes before first pitch to get thru security, climb the stairs/ramps and find your seats. After that, the rest of the experience is gravy.

Enjoy these seats and enjoy the game! GO YANKEES!!!