"The latest iPad app from Readdle, a company famous for its excellent productivity apps for iOS, has perfected PDF annotation and note taking on a touchscreen device."
The difference between this one and PDFPen from Smile on my Mac appears to be that this one actually is a note taking program along with a PDF annotater. Oh, and its about four bucks cheaper at $5.99 USD [affiliate link]. I also think that PDFPen is a bit more polished and has a couple of advantages namely it syncs with the desktop version and has iCloud syncing. But if you just want a standalone PDF program and like to take notes on your iPad, this one would work just fine. If you have used either program, tell us your thoughts!
iPhone 4, 1.6 GHz Core 2 Duo MacBook Air, Apple TV, 2.66GHz Intel C2D Mac Mini, 1TB TC, Airport Extreme,several iPods and an iPad, 32GB Wi-Fi version. Follow me on Twitter.