Really the only difference is the included StoreMI thing. All the OC/boosting stuff is either native to the chip (XFR2, PB2) or should be in recent/imminent BIOS updates on the B350 and X370 (PB Overdrive). Because of how well PB2 works it looks like, settings-wise, it's actually better to stick to stock (with Overdrive, if you wish) instead of forcing a somewhat higher all-core OC at the cost of single-/dual-core turbo. Better cooling removes that boost limit and better/better-cooled VRMs lets the removed-power-limit of PBO do its work. So it's basically a search for good components no matter the nominal chipset.
There's a B450 scheduled at some point but again there's likely to be no hardware difference vs the B350. Unless some new models get better VRMs, anyway...