Once and for all, there is simply no feasible way to use a true "fine point" stylus on the iPad's capacitive screen. If there were, Steve Jobs would not have spent time at the original keynote lambasting the use of styluses and promoting the use of one's finger. (Mr. Jobs as master salesman knew how to turn a product weakness into a "feature.")
Briefly stated, what any stylus does is provide a relatively wide contact "circle" on the screen. The capacitive screen sees the center of that circle as the "touch point." Most inexpensive styluses obscure that "touch point" in order to make a contact "circle." Thus, the user has to become accustomed to a particular stylus and their particular "style" in holding it to determine exactly where the "touch point" is.
The Dagi and the Jot (from Adonit) try to get around this problem by providing a transparent contact point that enables a user to see what the iPad believes is the touch point (i.e. the middle of the circle.) I have a Jot Pro and it works well as long as the miniscule current flowing between the plastic contact disk and the touch point is not broken. This has been a problem with some Jot's and can be eliminated by applying a (very) tiny dab of conductive grease (available at a hardware store or Amazon) to the point of the stylus. I've never used the Dagi but another poster here (Heaviside) has used both and maintains the Dagi is far superior. He's the guru of styluses and I'll take his word for it.
There are other options. A couple of manufacturers claim to have solved the problem with a hardware solultion that senses the placement of their proprietary stylus on the screen and transmits the position to selected apps. Personally, I'm skeptical. It's an expensive solution. Requires a separate device to be plugged into the 30 pin connector, and works only with some note taking/drawing apps. YMMV.
Finally, many users find the iFaraday styluses to be a good alternative. The contact points are conductive fabric rather than rubber. They're smaller than most other styluses and glide across the screen very easily. Although I have the Jot Pro, I find myself reaching for one of the iFaraday styluses more often.