I may be alone in this, but the S3 met my expectations as far as phone calls go. The phone that I had before it (iPhone 4) needed the Network Extender (1 or 2 bars at my computer desk) and the S3 needs the Network Extender, same 1 or 2 bars of cell strength. On the other hand, I find it far superior in terms of speed and display. Where the iPhone excelled was in battery life. I'm doing somewhat better with CleanROM and Lean Kernel than I was with the stock S3, but I don't think that there's any way that it could equal the iPhone's battery usage, due to the larger display and faster dual-core CPU.
And I always had to have the iPhone in a bumper case due to the "grip of death", don't see that with the S3. I don't find that how I hold it affects the performance. Again, it is a larger phone, so I most likely have to hold it differently than the iPhone, so that may account for my not seeing that problem. One of the knocks on the iPhone 5 is that it is easily scratched/marred due to the construction, so you pretty much have to have it in a case. I'm another one that has never had my S3 in a case, and it looks pretty much like it did when I got it.
So I don't have too many complaints about the S3, it fulfills my needs for a phone. And as much as I didn't want to have to root it and so on, that has given me the freedom to cut down on the Verizon and Samsung apps, and freeze whatever I want that the S3 doesn't allow me to uninstall or disable. Which also helps the battery life *smile*. And I can back up the content of the phone and app data.