Hmmmm, Orochimaru's was well planned out and failed mostly because Gaara was wounded and couldn't release Shukaku, which would've been a considerable turn to lay waste to Konoha. Using the Chunin exams as a guise was smart, even though he technically told Konoha about it beforehand in his meeting with Anko (By the way, where the **** is she? LOL).
Obito was smart enough to set up a plan to get Minato away from Kushina to extract Kurama and keep the Hokage separated from the village.
Pain more or less charged in there like a herd of stampeding elephants. He basically just used overwhelming power to get the best result from the three invasions. However, his goal was actually to find Naruto. Attacking was secondary.