I think it's safe to say, that whether or not any given phone has a backdoor intentionally installed or not, they're vulnerable to similar things. I went to a presentation by someone in a position to know, and he demonstrated just how easy it was to exploit the iphone, and assured us that all phones were similarly easy. Then add to that the technology available to governments, and you can further assume that any computer not being used in a secure environment (SCIF) is easily able to be monitored. The upshot is you shouldn't put anything in email that would be devastating if it became public. Ever.