Never heard anything bad about them. It just makes your o2s read correct so it doesn't cause check engine light to come on. Therefore you don't need a tune and the parameters aren't getting disturbed. As far as easy it's super easy as long as you have a jack and jack Stands 13-15mm sockets. Takes 1 hour including jacking the vehicle up.
Yes it will. But if you don't want to or don't have the funds for a tune. Then for the time being you would use mil eliminators so there's no ill effects of removing the cats.