Neither the A1ii nor the R5ii are on the market so no-one knows how they compare or why someone would buy one over the other. However, the R5 and A1 weren’t really targeting the same market given by the price difference between the bodies. I don’t suspect either camera’s successors will change their respective strategies to compete directly, so one reason to pick the R5ii would likely end up being your previous investment in canon glass in addition to a body which may be 30% cheaper. Whether that’s meaningful to your needs or not is a different story. For me, the improvements of the a1 over the R5, combined with the need to cycle all my lenses, and pay a ~30% additional premium wouldn’t make any sense if the R5ii and A1ii follow their predecessors market segmentation. I need absolutely no speed increase, no auto focus improvements, no ibis improvements, no video improvements, but I care a lot about image quality, weather sealing, usability, and certainly the needed investment for those improvements. I definitely don’t need my R5ii to be an R1 price point. But again, everyone’s needs are different, so you mileage may vary!