This may be a biome-adding mod, but get ready for a whole bunch of items you didn't expect- this one is pretty well rounded and adds an awful lot. It can definitely feel a bit bloaty at times, but there's a lot of upside.
The biomes themselves are innovative and fun to explore, except the mushroom biome (my opinion), which seems too repetitive to be interesting after a while. The swamps and volcanoes are some of my favorite. If that mushroom biome or anything else ends up being more common than you'd like it, you'll need to edit the mod settings.
Plenty of feature-rich items, or nodes with a lot of aesthetic appeal, make this worth the "bloat". The crystal tools work like Silk Touch in Minecraft, as well as providing a good reason to find the rare Crystal biome. The added fishing api doesn't seem to fit the mod at first look, but it has differing drops per-biome (fitting it into ethereal's biomes nicely), multiple species of fish, and a few interesting food items. This mod also offers a way to make infinite mese, although it's tough enough that only an experienced user could make a proper farm (and they get big!).
The mapgen is also quite light-weight compared to other biome adding mods. So - if you can handle the extra item count and like what you see - this is for you! Recommended.