Orochimaru doesnt jsut want the sharingan he wants to be the "strongest" even with a sharingan implant he cannot defeat the mange sharingan- and It is my theory that it is this ability that Oro actually fears about itachi- other than that im guessing their strength is fairly equal. I came to this conclusion from the fact it seems that Jiraiya didnt seem to have any knowledge of this ability( or had some counter for it, as he maintained steady eye contact during standoff ) Oro's experience with Itachi while in Akatsuki would have made it so he was prevy tho the abulit og the mange sharingan. a technique that he cannot defeat- unless he ahs not jsut the eyes but the blood of a true sharingan sucessor. otherwise he coule have jsut killed kakashi and taken his eye. H e wasnt Sasuke's bloodline ability of the mange sharingan.
Obito a chick...hrmm i wonder about that. it is possible i suppose that would make sense why he goes to see the grave every morning if that was his woman... unless it was jsut a buddy and he was responsable for his/her death and is constantly hhaunted by the gilt of thier death.