I played the Lost Planet demo recently on 360, and I ended up hating demos in general.
If it's a shitty game, I download for 5 hours only to delete it sraight away. If it's a good game, I play for 5 minutes and still end up deleting the demo, because what's the point of playing 5, 10 or 20 minutes of a good game? It's like foreplay without sex.
Playing demos of unreleased games sucks even more. From now on I will only download a demo if it is possible to walk 5 minutes to the store and pick the game up straight away. Demos are the devil I tell you.
On a side note, Inafune is on a roll. Lost Planet is a lot of fun, Dead Rising looks better with every trailer, and he seems to be a really cool guy judging by this IGN interview:
http://xbox360.ign.com/articles/707/707854p1.html
He makes some really interesting comments about the direction of the Japanese games market. Highly recommended reading.