I have used Xournal a lot on my 770 but on n810 I prever Maemopad+ for taking quick notes - no need to open and save files and it starts faster than Xournal. I am still using Xournal but only for longer writings - sometimes several pages. The following resumes my impression about Xournal:

• The screen of N810 is too sensitive for my habits so it was difficult for me to write pretty. However I put some very thick protector on the screen and now I am able to write well and I am happy. Now my N810 is less finger-friendly but this is not a problem for me.
• On N810 my hand is uglier than on a paper. On the other hand the undo tool means there are no deletions in the text and as a whole it looks better (and with colors).
• The PC version of Xournal can print the files you make.
• It is very difficult to write well without a support - a desk or your leg.