I have an iPhone 3GS and I love it (you probably should get 4S instead). I don't know if this is worth noting but I read that the iOS doesn't get viruses whereas the android OS can.
Bull, complete and utter marketing bull.
iOS has been MiTM'd, Ring-zero'd, C&C'd, malwared, zombied, and just about every other thing you can think of. It was even possible to zombie an iPhone with a simple corrupted SMS message. Arbitrary code has been successfully ran through pdf files, javascript (yes, Javascript! Apple thought it was wise to improve javascript performance by giving it kernel access), and the already mentioned SMS.
iOS is every bit as vulnerable as Android is. It should also be noted that iOS had the fraudulent diginotar certificates active for far too long, which would mean someone using an iPhone would be vulnerable to very convincing phishing and silent MiTM attacks to steal bank information.
What does keep most of the problems from surfacing on iOS is apple's absolute control over the AppStore, which limits (but does not nullify) app-based attacks. Successful app-based malware programs have made it past Apple's screening, so even that is far from foolproof. In the end, though market-based attacks aren't really the thing to worry about, and as far as rogue apps: http://www.latimes.com/business/technology/la-fi-tn-twitter-contacts-20120214,0,5579919.story?