Debian is fairly straight forward I think, I'd think maybe a half step behind Ubuntu and mint for being easy and accessible, but mint and Ubuntu both have communities that have a reputation of being extremely friendly to new folks just figuring things out
Just depends on what you need :) like the other reply said, mint debian edition is a great choice built by the mint folks to be very user friendly and with the mint community. Just keep in mind debian gets updates very slowly, so I'd expect mint debian edition to also get slow updates (maybe someone more familiar with it can chime in), which may or may not mater for you. But as a result it has a reputation of being absolutely rock solid (though so does mint. And regular mint is based on ubuntu. All the versions of mint ought to be extremely reliable)
Personally if you like one of Mint's interfaces (desktop environments) I'd probably just start with regular Mint. There are a lot of good options available though :)