I’ve been using BlueBeam PDF Revu on my tablet PC for some time now to present my classes (annotating PDF slides). So I was quite excited when I heard that the BlueBeam PDF Revu iPad app was available.
As you would expect, the inking is excellent. And it does have an advantage over iAnnotate PDF at the moment in that it chops up your annotation block into smaller pieces as you write, in case you spot a typo and want to delete it later. (With iAnnotate currently you can only delete whole blocks of annotations at a time once you have finished a particular block.)
Still, there is hope that these apps will continue to improve. Early days!