I have been using Microsoft Office OneNote since I started working 3 years ago, and my only issue has been that I wish I had known about it when I was studying. I consider it a critical part of not just my working life, where I use it to take notes on projects, keep minutes etc, but also my personal life, where I keep general clippings from the internet, ideas and other things. It is the first thing I open when I get to work, and when I turn on my computer at home.
I have been holding onto my N8 until I could get a worthy replacement in the Nokia family. I feel that the Lumia 925 is that, and it has just been made available in my country. Using OneNote on my N8 is a pain; it's very slow, and wouldn't work at all until I flashed it with some custom firmware. Also the 3.5" screen is not that great for taking notes.
Before upgrading, my question is, is there any lag when taking notes in OneNote on the Lumia 925 (and by extension, WP8 in general)? Does the app make good use of the available 4.5" screen real estate?