If you read exactly what this phone can and can not do on certain carriers this phone is not as capable as some Droid phones. Example galaxy s3 on Verizon can multi task, talk and check emails at the same time. According to Apple, there phone is not capable of this. According to them it is due to the antenna!! Just crazy. Not getting it.
What you are talking about refers to network technology, not a limitation with the device. Smartphones on AT&T and T-Mobiles GSM networks have been able to multitask for several years. Verizon and Sprint's CDMA networks are largely not capable of simultaneous talk and surf. This is one of the primary differences between GSM and CDMA technologys.
That said, I believe that LTE phones that are operating in VZWs LTE network coverage are capable of talk and surf, when you fall back to the 3G, you're stuck again having to choose, unless you are in a wifi environment.
All of Verizons LTE enabled phones can multitask Except the iPhone 5. Why? It is because of the radio that apple chose for the iPhone. So For the record it is a apple issue. Why folks can't multi task with a iPhone.