I used to think pen and paper was best, but since I got army builder (which is nothing to do with GW, btw - it just happens to allow you to build lists for GW games, along with pretty much every other wargame in existence) Ive found it to be much, much faster. It also integrates extremely well with my iphone (and if I had an ipad, itd integrate wi that, too) by outputting lists in such a way that you can list the units by name on one page, then poke at a unit name with your finger and itll show you the stats and special rules, and then if you poke at the special rule itll tell you what it does. All this nests in one screen. verra handy, I must say. Likewise, I expect the PP software to be basically a stack of cards on my iphone, with some army-buildy type functionality. As the cards come with the minis anyway, it's largely unnecessary, but it's one of those things that'll just be handy. The fact that it's free is a very canny move on their part, too, as it'll be really useful for people demo-ing games with the starter sets. Depending how easy it is to navigate, being able to look at your opponent's army cards could be handy, too. It's also handy as you still sometimes get the old Mk I cards included with minis when you buy em. I intend to get the cryx list and maybe the trollbloods. The fact that the digi sets also auto-update whenever a new mini is released for a faction is gold, too. No more needing to buy "new" decks for the new PP books. One download, and your up to date for all time. Marv'lous
Anyway, we shall see how it is when it comes out.