The difference between Obito's Kamui and Minato's Flying Thunder God jutsu.
This is how Obito's S/T technique beats Minato's, as admitted by Yondaime.
As you probably know, the only way Minato can teleport to a far away or a nearby location, or even a person....is by marking them with this
This seal, can only be placed on someone through physical contact, specifically, the palm of his hand. It is a very distinct and noticeable marking. Although... when Minato marks someone with this seal, it is quicker than lighting! No one has ever noticed this seal or Minato placing it, on themselves or anyone else, until Minato actually had a chance to use it.
How does Obito beat something like that? Well....he has a significant amount of help!
We all know Zetsu doesnt use hand seals. So essentially, it is not a proper jutsu. With the cells of Hashirama running through his veins, or should I say vines, Zetsu can use many plant based jutsu in a flash, on a level ranging from microscopic to who knows, maybe even Jukai Koutan.
In my opinion, he scatters spores that stick to the enemy on contact! These spores are organic and microscopic, probably the size of a single living cell that can also expand by self multiplication at a moments notice.
Here is when Zetsu cast his jutsu:
OOOOHHHHHHHH! I love that!
This is when Obito, in a sense marked Yondaime:
When Yondaime touched Naruto's blanket, he had the spores on him! The rest should have been easy, but Minato is not Hokage for nothing!
Go anywhere, find anyone, duplicate them, replicate them, all down to trace amounts of their chakra! Possibly even drain their chakra and send it to Obito?
Zetsu really is a marvel created from Hashirama's cells! What a 'thing'!
I cant remember the manga page, but Obito even asks Black Zetsu, if Kabuto had White Zetsu's spores on him!! That is proof enough, he can go anywhere with Kamui, anywhere that Zetsu has already visited, which is practically......EVERYWHERE! Zetsu is the land.
SO in conclusion...the difference between Kamui and the Flying Thunder God is:
For everyone who thinks I dont have enough "proof" for this:
Zetsu's words to Obito in the above image prove that Obito's Kamui is OP because of his Mangekyo Sharingan and Senju DNA fusing together!
Here is even more proof:
Obito goes intangible the second his Mangekyo awakens and the Senju side of his body starts reacting to it!
Need anymore "proof"?