1) My company currently provides all employees with Blackberrys through TMobile. But you also have the option of bringing your own personal iPhone and having IT set up email and security features on that. I'm hating using the blackberry so I was thinking of buying an old iPhone 4 or 4S. I would move the TMobile sim card into the iPhone and have the company set it up. My question is, whether or not I will be able to get 3G through TMobile on an AT&T iPhone (I don't think there was ever a T-Mobile version of the 4 or 4S). 2) Although I prefer to keep my work phone separate from my personal phone, the thought of having one device has crossed my mind. However, I do NOT have an unlimited data plan. I get dozens of emails per day and many contain large attachments. I would be afraid of going over my data limit with all these emails going back and forth. My question is this: If a large PDF document is sent to me via email, does that large PDF document count against my data limit if I do not open the PDF but simply read the text of the email? Thanks.