Lizard: Being Cold Blooded/Ectothermic and a Carnivore sucks. The lack of ability to wear proper pants is bad, but Reptilian Healing coupled with a wide range of melee combat and durability buffs means they’ve got a lot more longevity both in and out of combat. Would really shine during the heat of mid-Summer months, just leave them at home during Winter and early Spring.
Bird: NPCs are fragile enough as is, making them faster than you and much more injury prone sounds like a good way to end up with a dead mutant.
Fish: This used to be the red-headed step child of mutation trees, it still is just slightly less so now. I’d skip it for NPCs unless you want to start a cult of fishmen to worship your post-thresh Cephalopod or something.
Beast: More year round utility than Lizard, but with the caveat of still being stuck with Carnivore. They also gain a bunch of useless mutations and have a much higher maintenance cost to boot. Skip it.
Feline: Similar boat to Beast, you’ve still got Carnivore but the maintenance cost is the same as an average NPC otherwise. This means they don’t get any real major bonuses though, Long Tail is nice because they’ll train dodge a hell of a lot faster then usual though.
Lupine: Second verse, slightly tweaked from the first. Not having to worry about Carnivore is always a bonus. Fluffy Tail nets you that sweet dodge bonus. An okay, if non-offensive choice. Just be careful of losing track of them at night due running off with High Night Night vision.
Ursine: I probably enjoy playing a Bearman Survivor more than anyone. But being slowed from Ponderous and losing the ability to wear standard sized clothing or ride in vehicles with Huge basically makes NPCs useless.
Cattle: Same situation as Ursine. The toughness and strength increase just aren’t worth the drawbacks. Avoid it.
Insect: Like Lizard with the Cold Blooded shtick and general close combat boost, including an immunity to acid to boot. Spiked Tail is probably one of the best combat mutations as well. Though sooner or later they’ll probably get shot in the face due to not wearing a helmet with Antennae.
Plant: Most of the bonuses a Survivor would get don’t really affect an NPC and they get shackled with Extremely Ponderous. Avoid it.
Slime: I don’t have first hand experience with this one, but Hollow Bones is bad news wherever it pops up for aforementioned durability reasons. Slime also gets a mutation that amplifies pain apparently, that’s bad news because NPCs do feel pain and one good hit could render them combat ineffective if not outright kill them due to Hollow Bones.
Troglobite: Contrary to what you might think making someone a night crawler doesn’t make them a good night raiding buddy, due to them potentially running off after stuff they see with Full Night Vision. Regeneration means they’ll heal from anything that doesn’t kill them in short order though and with Saprovore you can just feed them rotten garbage to boot. Not a bad choice if you prefer operating nocturnally yourself.
Cephalopod: Slowed down by the whole “I’m Made of Tentacles Thing” and being Heat Dependent, along with the lack of ability to wear torso armor or a gas mask really sucks. Avoid it.
Spider: Not terrible, but the drawbacks of Carnivore and Heat Dependent along with the mobility restrictions placed by Furred Plate outweigh the potential benefits.
Rat: Benefits in the hands of an NPC don’t outweigh the resource cost in my opinion. Avoid it.
Medical: Pain? Acid? What do your followers have to fear aside from that, a bit of addiction or schizophrenia? Ha! This is a case where game mechanics really benefit a mutation category, all the downsides aren’t experienced by NPCs. The only issue you’ll run into is Genetically Unstable slowly throwing things outta whack, but with Robust Genetics it’s just as likely to balance itself out over the long term. A truly solid choice.
Alpha: Giving a follower +7/+7/+7/+7 stats is nothing to scoff at. The main issue is the barrier to entry. Alpha mutagen is expensive both resource and time wise to collect. That and due to combining Disintegration with Very Little Sleep you run the risk of them going into a fight with a quarter or more of their health shaved off due to degradation alone. Still if you’ve got one or two NPCs you are particularly attached to and don’t mind the micromanaging the HP there a little Alpha is the best bet for making them more effective.
Elf-A: Avoid it. Bad Back, Hollow Bones, and Radioactivity are all pretty seriously terrible for NPCs to have with only meager stat boosts to compensate.
Chimera: The ultimate definition of combat monster. This is the mutagen I’m most looking forward to experimenting with on people. You basically boil down an NPCs function to its most basic component, fighting in combat on your behalf. From there you’d just feed them the spoils of their work, to avoid the potentially massive maintenance costs while they continually sharpen combat skills to an absurd degree thanks to Apex Predator
Raptor: A combination of Lizard and Bird basically, they won’t be as tough as the former or fast as the latter. You’ll still have to deal with Carnivore along with Very Fast Metabolism and a lesser form of Cold Blooded. Probably better to just give them Lizard instead of a washy middle ground.
Edit: Holy shit, I just started jotting stuff down yesterday and it turned into this unholy amalgamation. I never really realized how extensive CDDA’s collection of mutation trees were.
Yes. Though you can still mutate from radiation with Radiogenic. So you’d end up looking like a bunch of walking freak shows sooner or later.