I do not know about the other readers, but for the Pocketbook the 902 or 903 would definitely fit your requirements. Bear in mind, though, that unlike the )nyx and the Knidle, the Pocketbook does
not have a Pearl screen - I can read on it quite comfortably, thouhg.
As for free hand note taking, this feature is currently implemented for files other than PDF. One great thing of the Pocketbook is that you can customise it in many different ways - I am still in love with my own device!
There is a full discussion of the comparison between Onyx and PB902 in
this thread - you may wnat to start from the video comparison directly, from
message 226. The short of it is that PB seems to dominate hands down on speed, but some have queried whether there were issues with the specific Onyx device used, and others have said these are things that can be sorted out by firmware. If I were you, I would first of all wait and see until the device you are penciling down does all the things you want it to do in the way you want them.