Since it does depend on the specific carrier and the specific location, asking a general question will almost never get you an answer. The iPhone 4 was about the only phone that ever had a "general" problem (the design put your hand over the antenna, killing the signal).
But in general? Where I live, AT&T covers everything like a blanket. But in the next town over, there's not a whisper of AT&T signal. Sprint works well there, and here - except in my house. It's always on the verge of "going digital) in my house.
So you have to specify both carrier (not the people you pay your bill to necessarily, the people whose towers you connect to - Straight Talk doesn't own any towers, so saying that you have a problem receiving a signal from Straight Talk doesn't tell us anything) and the general location. At least the city, and if that's large (like NYC), what part. (In NYC, actually, it can get down to fine signal except on one block of a particular street. The "towers" are antennas on buildings, and the middle of a side street may not get overage.)