Are you using a 3GS? I find the writing on my 3G to be too laggy for a normal writing speed, so I end up writing at about the same speed as I type in the 'regular' Notes app. I love the attention to detail and thought that has gone into it though.
The biggest new features in SDK3.1 were related to video, the rest were minor additions. A lot of developers target 3.1 accidently though because it's the default.
Awesome idea. It wouldn't surprise me if this interface "influences" some future apps that come along..
That said, it's verrry crashy on my iPhone, and other apps tend to be pretty solid for me. If he irons out the bugs over time, I could see this becoming a must-have for me. Distinct from other 3G commenters here, though, I found it more than fast enough to keep up with my scribbles.
FWIW, I found another app called FastFinga. It's not any good for doodling or drawing diagrams, but for the writing part, it trumps this app in usability (and non crashiness).
Putting the author's name in the title of the software reminds me of the eighties... In fact he's had his name registered as a trademark since '89. Smart move probably.