To be fair, that does look bloody good.
there is a risk of coming across as a fanboy when one says that.
Not really. You’ve quantified your reasoning and have experience of both systems. Seems perfectly reasonable to me.
Rather, the advice “get what I’ve got” with no other consideration for a poster’s requirements is what I’d say is fanboyism. It crops up time and again in computer threads (“buy a Mac” / “install Linux”), phone threads (Android / iPhone) and so on. Doubly so when it’s from a point of ignorance, people who think Windows is shit but haven’t used it since Windows ME days for instance. It’s frustrating and unhelpful.
I have no brand loyalties and have owned consoles from all of the Big Three previously. In isolation, if I were buying one or the other “cold” tomorrow then I’d probably get a PS4 just for the platform exclusives (though I’d miss Forza Horizon 3). However, one of the OP’s requirements is to game with his mates and his mates have Xboxes. That’s why the Xbox is the better choice here, and is also the primary reason I bought one over the PS4.