Are you sure that's the general working definition? I'm with @HGohwell on this one. Often, Anti-Villains are seen as villains who have ultimately good motives but they do horrible things to get to said goals. I mean, granted, an anti-villain could do something like pretend to be good and have ultimate motives. But I think usually, the following is what most of us are used to?
That being said -- I like working with anti-villains more. There's the saying that "everyone thinks they're a hero in their own story", and anti-villains fit this. With regular old villains, they're mostly portrayed as knowing what they're doing is messed up and just not caring. They might not be evil, per se, but they're not good people.
For me, Anti-villains aren't exactly good people either, but they also had the makings (and still can) have the makings of being heroes. You know, provided that they didn't do something you could never take back. And I like to explore the depth of how far someone is willing to go to "do the right thing", even when they know what they're doing might not be good.
Anti-heroes can do this as well, and I can kinda see where these two can mold together -- depending on your definitions of them. But for me, a lot of anti-heroes are very.."dark". Not like a Deadpool vibe (who adds comedy and self-awareness); it's more of that "The Punisher" vibe where everything's gritty and Noir. It feels like "Anti-heroes" are generally focused on being less light-hearted and not focusing on say, a hero who's cowardly/wimpy.