I don't understand anyone who has had problems making a call on an iPhone. I had an iPhone EDGE until October, and an iPhone 4 since and have NEVER had any problems making or receiving calls, at least not when I had signal. I did have issues in my home, mainly due to local regulation preventing a cell tower from being built locally. After finally calling at&t about my issue, they upgraded a tower on an adjacent island to give me, and my entire town full coverage. Apparently they had never gotten complaints, but once they received a complaint, they fixed the issue.
Also, the 'slow lane' jab is quite accurate. I work in a office where everyone uses a different carrier, and many use different OSes on their phones. Every once in a while we'll simultaneously do speed tests to see who wins, and it is usually my iPhone and the T-Mobile My Touch neck and neck, usually with the iPhone ahead by about 20 kbps, with the Sprint 4G phone (EVO) right behind, and the Verizon phones dead last, at barely dial-up speeds.
http://en.wikipedia.org/wiki/Comparison_of_wireless_data_standards
Just goes to show you that there is SOME truth in advertising.
TEG