the criticism section looks okay to me it seems to mention both the criticism and its counterpoint for most of the points it maes although it really really needs some cites whether or not other articles have criticism sections is fairly irrelevent to this one either the criticism in this article is fair or it is not tit for tat is not a valid reason to change it of course if you do feel there is sufficient criticism of ubuntu to warrant a section feel free to add it to the article