Originally Posted by El Presidente
Download an app called Network Signal Info, what does it say your dBm and asu is?
You also might be able to get this info via Settings -> About Phone -> Status (or thereabouts).
Settings > About > Network is where you'll find it (at least it is on mine, running a 4.3 Sense ROM).
Note that small variations in position can change these things - I just moved mine one phone width to the side and it went from -71 dBm to -69, moved it back, turned to type this, and it's now reading -75. So don't read too much into small differences, and if you compare 2 phones do swap their positions after a while.
Different phones, or different software on the same phone, give you different numbers of bars for the same signal. The real test is, as said, whether it works - if you can make and receive calls in all of the places you could previously then it's fine, whatever the bars say.