This is an incredibly fun mod. The characters all feel like how they did in their own games.
Though, for some people, perhaps how amazing they are moveset wise could be a turn off....
But, when I was messing around in a ROM hack. The base Mario moveset was better for the specific task. (Mainly, a tall wall jumping sequence.)
With all that being said, probably the most satisfying thing in this mod is the ability to kill enemies you normally can't.... Such as the Mad Piano. When I first did that, I was like "Oh my God, Zero is so cool!"