iOS and iPhones are definitely very good, and also very consistent—if it works well on iPhone 6, it’ll work well with iPhone 7, etc.
Some Android devices are equally good, but many exhibit worse Bluetooth performance, and some tend to have breaking bugs in their Bluetooth stack or Bluetooth controllers. I was recently debugging an LG device that had a buggy implementation of connection-interval-update-procedure, which means it couldn’t keep a connection with the beacon, preventing configuration and firmware updates.
Samsung Galaxy devices are generally pretty good. They have some quirks with their batch-scanning implementation, which I think used to sometimes mess up our SDKs. I don’t remember off the top of my head if we found a workaround for that already, and if S7 specifically was affected.