The Harley mount is probably superior. I also got Amazon quick detach mounts for both of mine. They aren’t perfect and needed a little bit of fitting but they also hold up well. I have heard the ones that come in multiple pieces aren’t all that great so both of mine are the solid type

(that probably doesn’t make sense so this is the one I got most recently Amazicha Detachable Two 2 Up Tour... https://www.amazon.com/dp/B082V3CG1W?ref=ppx_pop_mob_ap_share)

One of the QD clips came off at some point during a trip and I replaced it with some different Amazon clips. I just put some lock tite on it and haven’t had trouble since. Now I just double check them more frequently to make sure they aren’t working loose.