I've never really understand the difference between these 3 structures :

>ものすごいスピードで攻撃したのですが...
>
>ものすごいスピードで**の**攻撃**を**したのですが...
>
>ものすごいスピードで**の**攻撃**だった**のですが...

I wouldn't be surprised if the first 2 were totaly interchangeable, but what about the third? Does it have a particular nuance or is it virtually the same as the others?