What are this thread's posters' favorite and least favorite factions?
I don't think there's a faction in 40k I couldn't see myself collecting, at least collecting a Kill Team's worth of figurines.
Thinking my way through... When I started back in 2nd or 3rd edition I enjoyed Tyranids and Eldar. I also accidentally collected some Ultramarines. As Dark Eldar, AdMech, Custodes and Votann were added to the main game, I was excited enough about each of them to at least pick up their codex and some models. In the middle there I read about Malal and did have some Sons of Malice CSM, but holy fuck, fuck painting white and black quartered armor. Imperial or Chaos Knights, too, have captured my interest, but thankfully the FLGS hasn't had them in stock the past 3 times I've visited -- Quartered White and Black armor on a Imperial or Chaos Knight might not be as bad, come to think of it. Malal themed Renegade Imperial Knights? "The Brotherhood of Malice?"
Right now I collect Custodes intentionally and Space Marines accidentally. I have some Votann (the intro box they put out) and AdMech, too. If AdMech were in a better place I'd collect them, definitely. As it stands they're a complete joke.
So my favorite factions right now would be Custodes (Greek Demigods who could save the Galaxy but their idiot creator died before giving them the command to do so), AdMech (Stygies

, with Blood Ravens rounding out the third. Of course, part of the problem is I want to move away from playing
gwsdudes and work towards
mydudes. Like, I had an idea 500 pages back about an Irish themed Blood Ravens splinter group, that might be fun, especially if I toss in some IRA vibes... ...Zen Buddhist AdMech, that'd be doable with some more Asian themed cybernetic bits... I could probably soup in some IRA themed Guard with the Irish Space Marines...
Factions I just don't like at all... Whenever I think of factions I can think of at least a themed kill team worth of something to hold my interest. Genestealer Cults, Sisters of Battle and Necrons... can't even hit that level. Ok, maybe I could do an Antifa-hemed GSC, maybe using Orlock bits in a Kitbash. But Necrons... Eeeh. They don't feel like they have anything that you could do
mydudes with, ya know? Sisters, meh. Imperial Guard? Meeeeh. I wager if I dug through their codexes (guess I'll go grab some PDFs tonight) that might change.
So least favorite would probably be Necrons, Guard, and GSC. I could do something fun with the Sisters, maybe (do them up like Ironlilly's faux crusader color color scheme, and give them some AOS/WFB chainmail bits too, for example) and Guard. But outside of a meme GSC KT, I just don't get the point of Necrons and GSC. Meh. Meh I say.
Edit: Necrons deluding themselves into thinking they're something else, like a Medieval Knight Society or Theater Troupe or something, that could be fun -- but it's basically just staling from AoS at that point, innit?