One of my biggest peeves with manga releases in the West is censorship. Alot of Viz's titles are censored, especially if they are Shonen Jump.
It does annoy me in Eyeshield 21 when Viz tone down Hiruma's language. Usually, I don't like vast use of the f-word, but in certain places, it's acceptable and even necessary to use it excessively.
I am not too sure about this. scans and fansub for me made the whole industry make a huge boost. I ended up buying manga and dvds of series I already read/watched that I would have never bought otherwise.
I agree with this. I have bought most chapters of Eyeshield 21. I probably wouldn't have known about most of the fantastic stuff in it that the abysmal anime missed out or replaced with filler or other crap if the scans weren't available.
As for Sengoku Basara. It's good to see Hideyoshi, but unless Honda Tadakatsu returns, I'll pass.