I'm on the deWalt 20/60 volt system, but everything you said applies to either, with trivial details as the difference.
When buying battery operated tools you need to decide in advance are you buying a single tool, or a battery system. If just a tool any mid-range drill/impact works (face it, that is what everyone is buying who isn't buying a system). If there is any chance you will buy any other tool it is either DeWalt flexvolt or Milwaukee m18 because both have a large catalog of tools that fit your one battery which is convenient because it means you will always have a battery charge to finish the task.
When buying battery operated tools you need to decide in advance are you buying a single tool, or a battery system. If just a tool any mid-range drill/impact works (face it, that is what everyone is buying who isn't buying a system). If there is any chance you will buy any other tool it is either DeWalt flexvolt or Milwaukee m18 because both have a large catalog of tools that fit your one battery which is convenient because it means you will always have a battery charge to finish the task.