My husband says the iphone is a very clever device but as a phone it has problems. If you are in a low signal area you will suffer from drop outs and dropped calls. You might find it will work ok outside but when you go inside the workplace or house then you might have these problems. The iphone has poor sensitivity and so needs a stronger signal for reliable calls compared to most other phones. It doesn't matter if it's on the Telecom, 2 degrees or Vodafone networks, it will have these problems.
Because of the aerial design on the iphone, it is affected by the way you hold the phone. Other phones are affected also but to a much smaller degree.
He knows this because he gets called to look into call quality problems for one of the cell phone networks. The problem is almost always found to be much worse where the users have iphones. He went to one last week where the business had bought iphones for their staff and could not understand why the only person not having problems was the manager who also had a Nokia flip phone. It never dropped out and that's why he used it when in the office.