Had it for a couple of days now. I've used a HTC Desire for a couple of years before that. Some reflections:
a) Browser; The HTC actually has a better browser. When you zoom out or in the window will resize text to fit the window, with the GN you have to fiddle around before you get the size you like. This off course is off set by the larger screen.
b) Size: GN is almost double the size. I would probably not use it for extended conversations, my BT headset will get more mileage. But, the size was also what attracted me in the first place, you just don't stand in the store and have a pretend phone conversation for ten minutes.
c) Screen: It supposedly has a higher resolution, I just don't see it outside the larger real estate. That real estate is mighty handy though. I've been watching podcasts something I would rarely do on the Desire.
d) UI or Sense vs. TouchWiz: TW lets you scroll through the various screens something Sense doesn't, on the other hand Sense comes with a nice collection of Widgets. There is only one World Clock and that is fairly large. I like a small world clock on top of some home screens where I have apps related to a certain time zone. So I have opted for a different setup on GN and still need to make changes before it it optimized.
e) Input: Galaxy Note is hands down winner. HTC doesn't support external BT keyboards and Swype (I installed SlideIT on the Desire) is very efficient, not touch type efficient but a close cigarillo. I can see myself doing some serious note writing on it.
f) S-Pen: On a Desire you can only use a capacitive stylus with their rubber tips, the S-Pen is a lot more versatile. I feel like I may need to press a little hard and that creates some concerns for scratching the screen.
g) Bundled software: Samsung has a nicer collection including photo editing, just don't know that is something I will actually be using, it is a nice touch though. The King though is obviously the always available S-Memo, the ability to take a note while on the phone makes it into a productivity tool that reaches a different level.
h) S-Memo: As good as it is, it still has some annoying limitations. I would like to be able to recall the latest Note. Say you take a note in one conversation and then you need to use the content of that note in your next conversation, but then you will need to go out of Phone, back to home screen open S-Memo, find the note and then open it. A triple click with S-Pen should do all that.
i) Reading eBooks: Whoaw!! It is a very, very good container for the Kindle app (still haven't had the time to get around to epub, I can't download the Sony Reader app). I am able to set it to the smallest font with the most lines and smallest margins and my old eyes are still capable of reading without a problem. In bed this beats my Kindle hands down by the ankles.