This soft, flexible stylus is one of the simplest and best accessories for the DS.
Although it's not very pretty, you have to admire the elegance of the Comfort Stylus. It's a stiff but bendable wire surrounded by soft rubber, with a hard plastic tip like any other good stylus. Surprisingly, you can hold this thing like a normal stylus, and it works pretty well in that respect. You can feel it bend if you grip it too hard (I use a death grip to avoid any slippage), but the wire inside is stiff enough that the overall shape and angle of the tip are not really affected by a small bend in the middle.
Of course, the real purpose of the Comfort Stylus is not to be used like a normal stylus, but to be wrapped around your finger or thumb. The design lets you make whatever shape feels best. It may take a lot of experimenting to find what you really like best, but chances are you can find a configuration that is indeed very comfortable and very functional. You can put the tip almost parallel with your thumb and use the stylus like an alternate version of Nintendo's own thumb strap nub. You can set the tip to protrude from your fingertip, so you can play "finger painting" style without actually getting fingerprints on the touch screen.
The practical value of such a setup depends on the type of game you're playing. Games that are primarily displayed on the touch screen can be hard to play with the comfort stylus attached, because your finger or thumb will usually be covering up an important part of the screen. This problem tends to offset the gain in speed you get from having your muscles work over a shorter distance, which is almost a big help in fast games like Trauma Center, Meteos, and Ouendan.
Attaching the Comfort Stylus to your finger or thumb makes more sense for games like Super Mario 64 DS and Metroid Prime: Hunters, in which you control with the touch screen but actually spend most of your time looking at the top screen. Unfortunately, there are currently not very many of this type of game on the DS, but certainly there are a few very good ones.
And that leads to what may be the best part of the Comfort Stylus: it's cheap. The accessory may only make a big difference in a couple of your games, but that's not so bad considering the thing costs about five bucks. And it feels sturdy and durable, likely to last a while as long as you don't bend it wantonly.
It does everything the original DS stylus does, and much more; the difference is not so pronounced with the DS Lite, since the Lite's redesigned stylus is longer, thicker, and just plain easier to hold than its predecessor. Nevertheless, if you hate the idea of playing games with analog-style controls with a long stylus, the Comfort Stylus can help bring your fingers much closer to the action.
The Comfort Stylus is currently available only from the manufacturer's website, ComfortStylus.com.