I just finished watching Yu Yu Hakusho online and would like to compare these to in battle. Yusuke is a hard core Street Fighter, while Naruto is a Super Ninja. As a Ninja Naruto has way more techniques, and weapons under his belt then Yusuke does. However Yusuke has never needed such weapons since his entire body is a weapon being a S Class Demon.
Normal Fight Feats:
Yusukes Punches before the start of the series was enough to crack a normal human rib cage like Kuwabara's every time they fought when he said "O Ya the sound of your rib cage cracking does sound familiar". Now before he fought Sensei he was able to throw knockout punches to the Mad Doctor with every punch and even had to end up killing him with a punch to the head which broke his spinal cord. The Mad Doctor was a Psychic who was able to pull a Kabuto. Those feats are still before he even awakened the Demon inside of him which he was able to devastate a Mountain the size of the Hidden Leaf Village into rubble.
He can create thousands of shadow clones making him into a one man army. His normal Rasengan can only make a crater the size of Yusuke's normal punches. Most of the time Naruto will use his Shadow Clone technique as a diversion for him to hit someone with his Rasengan at close range. His Giant Rasengan can pack a much bigger punch but if Yusuke can shoot him with his Spirit Gun its game over.
Both Naruto and Yusuke have master a form of Nature Energy. Yusuke with Sacred Energy, and Naruto with Sage Mode. They are virtually the same thing since both animes require energy from the surrounding environment. Both are Human Demon Hybrids as well. And both animes have seen them combine there Demon Energy with Sacred Energy. To form a union of the two.
Who would win? No prep either. Both can also use a Thousand Years of Death to lol.