I do use an iPad but have a wireless keyboard - that makes it much easier to type a longer report/letter (although I do find the keyboard needs the lightest of typing touch!)
I found a very comprehensive review of using the iPad as a word-processor -
http://www.macobserver.com/tmo/artic...ng_on_the_ipad
I haven't looked into other tablets, etc, but I guess there will be other reviews out there.
Margaret