It must be stylus month on Kickstarter, with first the Cosmonaut and now the Flow appearing on the funding website. Like the Nomad Brush, the Flow by Joystickers is modeled after a paintbrush. The Flow has capacitive bristles rather than the traditional foam tip to more closely match the tactile experience of painting with real paint.
One of the things that's always frustrated me when painting on the iPad is that the friction from both my finger and any of the styluses I've tried isn't quite right. It can work very well for sketching, but when I open up ArtRage and start using a paint tool, there always seems to be a bit of a tactile disconnect from what I'm doing. A paintbrush that works with the touchscreen seems like the best possible solution short of pulling out real paint and using your iPad as a canvas -- which we definitely do not recommend.
It's important to keep in mind that brush stylus is just a tactile enhancement; the iPad is not pressure sensitive, and it will only register the brush as a single touch point. There may technically be ways to cheat pressure sensitivity by measuring the size of the touch, but unfortunately, that's data only accessible via private API calls in iOS.
What differentiates the Flow from the Nomad Brush seems to primarily be in the type of brush it was modeled after. While the Nomad Brush most closely resembles an ink brush with long bristles and a straight handle, the Flow is more like a traditional paintbrush with shorter bristles and a tapered body. Judging from the demo videos, it also looks like the Flow has softer bristles that may glide across the iPad more smoothly.
Like all Kickstarter projects, the Flow needs your help to become a reality. The project is designed by two engineers who decided to build the products they want to use, and they've set a modest goal of raising $10,000; with 26 days to go, they're already nearing $4,000. The Flow will retail at $29.95, but Kickstarter backers who are willing to help launch the Flow will get one for $20 (including shipping in the US). That's a deal I certainly don't plan on passing up.