I've been playing with the iPad app Paper by Fifty-Three. It's a drawing app. I'm not very good. But I try and sketch something every day and hope that practice will make me better. So far it's not working. They have a companion stylus for Paper, called Pencil by Fifty-Three. It's shaped like a carpenter's pencil. Comes in two styles - classy walnut and cheap aluminium.
You can use it as a plain stylus and it will work on any iPad. But if you want to use the special features of the Pencil, you need Bluetooth 4, meaning iPad Minis, and iPad 3 onwards. My old iPad 2 could not use the new features.
It's got a nice stylus rubbery thing to write with, you can press down and the pressure is registered and does things. The end is an eraser. The Paper app can recognise where the stylus end is and where your hand is, and basically it's a smart little doodad.
My aluminium Pencil arrived today and I've been playing with it. It's nice. I am not using the pressure features or anything special, just using it as a comfortable stylus. Very comfortable using it with Paper. It hasn't improved my drawing at all, it's still just the crappy doodling I am capable of.
Paper has a nice connection feature. There's a small circle at bottom left in the menu. If you press the tip of the Pencil in that circle, it syncs with the Pencil and knows that it's being used. This is really easy, and really neat.
The Pencil pulls apart easily so you can recharge the battery inside.