The Pepsi Porch is perhaps one of the most underrated seating areas at Citi Field. I've sat here for more games than I could count in sections 301 through 305. I'll review section 305 since it's thought of as the worst section of the group.
It's nestled in the far corner of the right field outfield. We couldn't see all parts of the field due to the angle of being in foul territory, more specifically the warning track in right field. Imagine having to rely on the fans cheers when the ball travels there. The foul pole was in our peripheral view but it wasn't bothersome. Citi Field is the only MLB ballpark with orange foul poles.
Citi Field is on the outgoing path of La Guardia airport (where most of the hotels near the ballpark are located) and the planes are constantly flying over the stadium. It can become kind of distracting.
Overall, I would have to say section 305 isn't for everyone - not everyone will enjoy these seats but for most games, attendance is pretty low so there should be plenty of other seats you could sneak into.

Everything at Citi Field from tickets to parking to concessions and game programs ($5) is cheaper than at Yankee Stadium. If visiting New York City, you should plan to see both if you've got the money to blow.