On both survival (Linux Forks) and creative servers (C&C City Server), I found that the gaming experience was improved in both cases. In survival, it add more features (e.g. proper trees instead of the nearly useless bushes) that is extremely helpful for survival players. From another standpoint, it is useful for creative and building players since all blocks' appearences are very nice
But on the another hand, the mushroom biome is too large and those mushroom trees are quite ugly. I think developers can refer to the appearence of big mushrooms in Minecraft, to create beautiful mushroom biome.
Overall, this is a good mod that I recommend to any server.