So now I find I am in the situation where I could upgrade to a N800. Is it a must have upgrade from the 770 or not?

I upgraded the 770 to 2007HE, and apart from the wireless no longer working and the change of image, I really can't see that much of a change (well, other than I can use the official version of aisle riot rather than my own compiled one). Is it just the speed, and the upgrading to 2008 processor speed, does that reduce battery life?

I also (as I stated before) really love the form factor of the 770, especially the cover, and not a great fan of the 800. So I guess I need a reason that outweighs a design without a built in screen cover.