My experience is that I have 3G connectivity issues with 4.2.1. The OS works very smoothly as it always has, no freezes or lockups. However, I have noticed that with apps that connect to the internet, either the integrated ones like App Store or ones I have added like Speedtest.net or various business apps, occasionally I will find that it will take an inordinate amount of time to connect - eg checking for Updates in App Store. With some apps it will even show that there is a network problem.
I have 4.1 GM on one of my computers here and I am able to go back to 4.1 and forwards so I can do a direct comparison. With 4.1 I do NOT get these network issues. Checking for Updates in the App Store gets an answer almost invariably within 10 seconds or so. With 4.2.1 I can wait over 30 seconds although for the most part it too will be quick. Speed tests show generally speed is much higher with 4.1 than 4.2.1. This indicates to me that either I am having high packet loss or the 3G data connection is dropping and then being reinstated.
I have reset network settings, reset all settings, restored as a new phone without using any backup afterwards ie. as virginal as I can possibly get it and I still have this issue. Being able to switch back and forth between firmwares is able to confirm this without a doubt.
That being said, I really like my phone. I have hardly ever had the proximity issue, I do not have lockups, no dead or stuck pixels etc. I really do not want to make a genius bar appointment and perhaps get a new/refurbished phone.
My thinking is that with alleged rumours of 4.3 coming out next month - Just a rumour - I will wait until then to see if the problem is fixed. I am fully aware that I am in a definite minority with my particular problem. Conceivably, would upgrading from 4.1 to 4.2.1 be best done in DFU mode or restoring to the latest version and setting up as a new phone should most definitely be good enough?
