The two most recent chapters have focused primarily on the Vandenreich. I like how Kubo is giving us exposition about the new villains, and it appears as though the ranking / strength system Yhwach uses for the Stern Ritter use is different than what Aizen used for the Espada. First off, it seems that every Stern Ritter is considered equal under Yhwach, since the arguments between Bazz-B (Stern Ritter "H", the mohawk Quincy) and Jugram Haschwalth (Stern Ritter "B", the bishie) were regarded as "infighting" rather than "insubordination". However, despite their equal rankings, I don't think that the Stern Ritter are equals in strength, since we saw five of them (Driscoll Berci "The Overkill", Berenice Gabrielli "The Question", Jerome Guizbatt "The Roar", and Loyd Lloyd / Royd Lloyd "The Yourselves") die during the Vandenreich's first incursion of Soul Society. Anyways, with that aside, I'm thinking that Haschwalth is the strongest of the Stern Ritter (excluding Stern Ritter "A", Uryū Ishida, for obvious reasons), since he managed to cut Ichigo's old Tensa Zangetsu in half with seemingly little effort on his end. Bazz-B claims that none of them would have minded if he was chosen as Yhwach's successor, adding more fuel to the fire.
Sorry for ranting.