Total Recommendations: 1
Both feature Shingami/Spirit Detectives in Yusuke and Ichigo. Both have female Shingami guidance in Rukkia and Botan. Rivals that become integral teammates like Uryu and Hiei/Kurama. The characters power up with Sprit energy in one and Spiritual Pressure is the gauge for strength in the other. Yuu Yuu is older and has a bit more of a comedic edge to it and less filler but the overall themes at the beginning are very similar. As the series goes on you have some of the half demon/ half hollow dichotomy as well so the parallels continue.