I use an iPhone 4 and I dislike iTunes. I prefer using USB file transfer because it's universal and I don't need to install Apple's software. Also if I want to select an MP3/OGG file as a ringtone I first have to convert it to .m4r then use iTunes to drag and drop. And as for SMS tones it's impossible even with iTunes unless I jailbreak.

Jailbreaking voids your warranty (iPhone 4 had lots of minor issues like faulty Home button), makes direct upgrades to the next version of iOS harder (have to wait for new jailbreak software) and in some cases worsens battery life. Anyway you still can't avoid iTunes sometimes because certain applications require it.