One of the best, if not the best, mods of its genre, but not perfect

This mod is just awesome on so many aspects. There are too many features for me to go over all of them, so in a nutshell i think the systems, mobs and items introduced by this mod are very polished and go together really well to form a genuinely terrifying and diversified threat to the player. It even has its own soundtrack which is honestly gorgeous, and fits the feel of the mod really well. It also is open source (though their github is currently private at the time i'm writing this, as they are working on a a very big update), has a very extensive config file and wiki, and a channel in their discord server where you can contact the devs, so creating a modpack around Spore is also very convenient. This mod even has a couple interesting addons too which you should consider if you're playing with this mod.

While i do believe it is an excellent mod, one of my favorites even, it is not perfect. My biggest issue with it is that it can be a bit frustrating to play with vanilla world generation: the infection can develop in random caves, which can make finding infection clusters to get rid of them actually annoying instead of being a fun challenge. It isn't an unsolvable issue player side (if you have a custom worldgen without caves or with very large caves, or if you enable the Spore config to move its stuff at the surface), but still something i think you should be aware when playing with this mod. I have some other more minor pet peevee in terms of gameplay (imo it sometimes borders the unfair/grindy territory instead of being the fun kind of challenging, though the mod being configurable can help a lot with that), but this is probably the biggest one. EDIT: in my opinion an other thing that makes this mod very hard to work with sometimes is how hostile it can be to player progression: your bases, contraptions, chests, etc... will not be safe, and the potential Spore has to sometimes erase progress can just be super discouraging

It is kind of a wiki mod, as a lot of things about it are not really documented in game (ex: the tech blocks, one of which is intended to be the main way to repair Spore armors and weapons, the uses of certain special items like the reaver and the scanner, the weakness of spore mobs to cold). While some infos being ambiguous genuinely contribute to the atmosphere of this mod, the way the mod explains like nothing in game can make it kind of a pain to get into. Honestly you'll probably still have a good time if you jump into it blind, if you're into that kind of mod, but you won't be able to experience this mod at its full potential, which imo is really a shame.

On the more technical side, if you're a modpack dev you can run into issues as some features are implemented in a kind of quirky way, which occasionally makes making it work with some other mods kind of a pain. For ex, certain blocks only drop their drop if they are specifically destroyed by a player, the Bile is not properly implemented as a fluid which causes some compatibility issues, etc. However this is expected considering how complex this mod is, and since it is still in (very) active development i believe we can expect the mod to improve on the technical side of things over time. They even have a bug report forum on their discord server!

For an infection mod, in terms of performance it also does quite well though not very strong systems can definitively struggle with it. This is something they also are working on, though.

So, should you give Fungal Infection: Spore a try?
If you're a fan of infection mods, or even if you're just trying to find something extremely threatening to your world, then yes, absolutely. It is not without flaws, but it is still one of the best mods of its category out there in my opinion. Be aware it can be a very destructive mod though (although this is configurable).