There is no one "best phone." It really depends on the user and their needs. For example, my dad is using some old motorola flip phone from like 6 years ago. I let him use my iPhone for a little while, then he gave it back saying that it was cool but he had absolutely no reason to use it over his phone, and that his motorola was actually better for him because its battery lasts like a week, and it won't get destroyed if he drops it.
Also, your question seems to be "Which phone OS is best?" not "which phone is best?"