In My Lifetime, Vol. 1 featured a jiggy Jay-Z and the sort of material shown on there sort of contradicted his image. It may seem like he's selling out due to this being radically different from "Reasonable Doubt" but some of the tracks he has are dope. Who You Wit II, Face Off, Rap Game/Crack Game, Where I'm From so he hasn't lost the street edge.
What makes this his most disliked album however are tracks like "Always Be My Sunshine" and "I Know What Girls Like", those songs contain the worst subject matter, worst beats and worst atmosphere. It doesn't seem like songs a rapper from the drug game would make, they seem like songs someone trying to desperately break into the mainstream would do and Jay-Z was a poor fit for the mainstream.
So yeah, some parts are underrated but it's disliked for a reason; too mainstream.