Okay, so far I've bought both uPad and NoteTakerHD. At first I bought NoteTakerHD for a while, then finally decided to buy uPad since I liked the smoothing of the handwriting.
Overall, uPad makes my handwriting look really good compared to NoteTakerHD.
A few things bother me in uPad, and hopefully they'll be fixed later on.
1) When you use the "Magnify input mode" for writing it greys out the screen; when I exit and reopen that input mode, it starts you allll the way at the top. Very annoying if you're far down the page.
2) You can't move text around like you can in Note Taker HD. So if my instructor decides to edit his/her notes, I'd have to erase or write tiny next to what I wrote. In NT HD, I can select and move my work easily.
Overall, I still like uPad more. Mainly because it's simple and your handwriting looks TONS better on uPad than any other app I've used.