I always thought that Kidd was way weaker than Luffy :
-> He has been defeated by ( probably ) Cracker π.
-> in the movie Stampede he is clearly not on Gear 4 Luffy level.
But Lately I changed my mind.
-> He has been defeated by Cracker but Luffy would have been too if it wasn't for Nami.
-> He was a rival for Luffy during the training in Udon.
-> Kaidou ( maybe ) considers them alike. 2 Brats possessing the Conqueror Haki and challenging him in a fight before being destroyed
-> He has been defeated by ( probably ) Cracker π.
-> in the movie Stampede he is clearly not on Gear 4 Luffy level.
But Lately I changed my mind.
-> He has been defeated by Cracker but Luffy would have been too if it wasn't for Nami.
-> He was a rival for Luffy during the training in Udon.
-> Kaidou ( maybe ) considers them alike. 2 Brats possessing the Conqueror Haki and challenging him in a fight before being destroyed