I have played the 1.12 version the most but have only very recently tried again its most recent version; since it seems they are two different uploads with varying content I will rate them both individually

What is it ?

A biome-adding mod which aims to stay true to vanilla Minecraft as it features few new biomes with little to no new blocks;
Most of the biomes being added remind me of pre-beta 1.8 environments.

What does it offer ?

New biomes to explore added to the vanilla worldgen, which feel closer to older now removed biome concepts such as with the oak forests (here as the woodlands) , the seasonal forest (autumnal woods, now most unique, featuring new blocks/trees) and the shrubland (now as desert shrubland) ;
Most of them are actually ideas inspired by another older mod called Extra Biomes, which have been implemented in recent versions.
(Short Biome list (found on the mod page too) : Autumnal Woods , Coniferous Forest , Desert Shrubland , Flatlands , Lush Swamp , Snowy Coniferous Forest , Woodlands )

It doesn't really have any major issue (none that I have noticed at least), outside of the fact that making custom biomes or even dimensions using vanilla materials has been done time and time again using datapacks in modern versions of the game, which means that this mod while certainly Good Enough is not really doing anything exceptional.
One flaw I have noticed (and that is even more apparent now) is the lack of decorations. Many biome mods come with either larger terrain modifications or more smaller-scale improvements like the presence of more ferns/tallgrass/bushes/rocks or more unique patterns for their soil and it seems this biome mod keeps the ground somewhat barren making them feel less interesting to traverse through compared to many other biome mods.

In conclusion

This mod can serve some purposes, but is outshined by plenty of worldgen datapacks and current mods in recent versions at least (such as Environnemental, Regions Unexplored, Terralith...).
There is a wiki giving more information about each biomes added, and you can decide in the configs which biomes appear (even if you cannot do much more).
I will check Terrestria for the first time afterwards, to see if it is a similar cake with extra modded materials or something more out of the ordinary.
Traverse seems to be much different in 1.12 (as I remember seeing more interesting environments than in this iteration; it seems to be a separate upload from modern Traverse, so I will take the time to note it separately).