Siri in real life? Not great to say the least. It's not bad, it's slightly below okay. The iPhone 5 will release this year, soon, in a couple months at the most. It will be the first iPhone with 4G, I'm sure. Stick with your phone until then.
Don't start. I have a iPad 2, but to tell you the truth, I like my playbook tons more. But, the iPad is a awesome product, I won't lie. I always have always liked macintoshises, might even do a hackintosh. I wouldn't get a iPhone, but if you want one, get one.