Research...
Minato Namikaze: Minato's sealing prowess can argueably match an ordinary or possibly a fairly high level Uzumaki (We've seen little of a true Uzumaki's sealing prowess but rumors about Mito Uzumaki and Kushina's prowess can be held). He has the ability to release the control shinobi have over their summons
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He can create a barrier that manipulates space and time, which can be assumed from the demonstration with the Tailed Beast Ball, to be able to telport matter into a different area as well as keep anything outside of the relm it controls out.
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We know of his Flying Thunder God technique which, through kunai branded with a seal allows him to leap from one position to another where anothe seal is locate, and also that the seal can seemingly travel from the kunai onto other surfaces. He also has the summoning technique which he has been seen to have a fair amout of ability in. His only offense seen is his Rasengan, which is of his creation, and the Shuriken shadow clone jutsu (only seen in the movie, however if any wish to rule that out that's fine)
Minato also has knowledge of the Four symbols seal, which is more of a basic foundation or formula for jutsu to be derrived from (example the Tori seal and Eight Trigrams Sealing style).
Nagato: Although descendent of an Uzumaki, whether or not he knew how to used such sealing jutsu is unknown. He possesses the Rinningan which gives him the abilities the Sage of 6 Paths had. He has his six paths of pain, which have linked vision.
Assura: depicted as a mechine with high amounts of strength and multiple projectile and mechanical functions
Pretta: A path with the ability to absorb chakra based ninjutsu (generally offensive in nature)
Naraka: the ability to ressurect life of other paths or even humans (through outer path)
Animal: multiple summons
Human: The ability to read minds and extract souls
Deva: The ability to manipulate gravity (almighty push/pull, Chibaku tensai)
All of the Paths also have displayed to a degree a level of speed, power, and taijutsu ability which is above the average shinobi's level. Also prior to popular belief Nagato has abilities in genjutsu (his mental blockades as seen in the Ame shinobi during his interrogations) however to what extent his genjutsu prowess is beyond that is unknown as well. Nagato also has the ability to use all five of the basic elements thanks to his dojutsu as well as YinYang release.
Should've put this in the beggining of the thread.
I've made a decision for myself. I'm going with Minato, but really I believe that shinobi at these levels of skill the decider would be the smarter fighter.