On the bad side, there's a bunch of child-like characters that are sexable.

There's also the slight addition of range to the combat system, where you can put distance between you and your enemy to make better use of your ranged weapons, but they can do the same.

On the good side, a lot of characters are interesting, sexable, and aren't children. It isn't horrible, but you may find that you have to reread scenes here and there to understand what's happening. Xianxia adds soul force, a bunch of new characters and dungeons (not all characters are sexable), but has some problems when it comes to the coding and definitely some problems when it comes to grammar and sentence structure. Xianxia and HGG seem (at least to my understanding) to use UE as a base for their content. Unofficially Expanded takes the base CoC and either adds new scenes, or brings back cut scenes/characters, while editing some existing content. Based off of my own experience, each is their own thing.