I mostly use her to place calls and occasional texts. Sometimes when I'm lonely I'll ask her what my name is. Her answer varies depending on if I've been watching Beavis and Butthead, Breaking Bad, or just being my own bad self.
Mostly just voice dialing and music playback. It works a lot better on the 5s than it did on the 5 (probably the iOS 7 update), but isn't flawless and I wish it didn't rely on internet for music playback and voice dialing. It was faster and more reliable when it handled them locally (prior to Siri being launched).
Siri is useful for commuting and when it's raining, I use the earphones to change songs and send messages, I really like that.
I don't use it too often to send messages because it gets the pronunciation incorrect. So I'd rather type it out.
Situs is pretty useful for commuting. And or when your hand dare wet or it's raining and you have earphones plugged in. I like that. But tiger than that I don't use it. Even when I'm lazy to type, is rather type than dictate because chances are it would make a mistake lol.
I'm guessing it's iOS 7. I'm not sure how hardware would help. The problems seemed to be with the network and speech recognition. I still get the occasional, "I'm really sorry about this but I can't take any requests right now or there is a problem, please try again later" messages but it's not as frequent on iOS 7.