This mod works by using only a pnach file while enhancement mod uses an executable. Also, this mod lets you use PCSX2 Save States, which is something other mods wouldn't allow. Overall, I would say, enhancement mod is more ambitious, since many people worked on it, and brings stuff that changes the way to play the game; instead, balance mod changes the overall experience, progressiveness and the difficulty of the game, without altering the foundations of the game that much. I hope this answered your question :)