I have an 4th generation itouch right now, and it's great except that the battery runs out after 2 hours. I also remember seeing a while back that some devices have less app-crashes because they have more horsepower, or something. The app does shut down quite a bit, though I haven't upgraded in about 3 months.
So, I'm considering getting an Ipad for the better battery-usage, and I'm wondering if those who have used both devices think the Ipad has less crashes than the Itouch. If so, then that will make it a really easy decision for me. If not, then...I'll consider it