Flame of Recca is one of my alltime favorite series. Yes, there's a bunch of huge parallels between it and YYH at the beginning, but towards the end and becomes very creative and brilliant. The latter volumes have absolutely GORGEOUS artwork.
And yes, the SODOM arc is all kinds of awesome. Anzai pretty much pulled out all the stops.
I love Domon, one of my alltime favorite manga characters. Joker, Kukai, Meguri Kyouza and, of course, the Crow Brothers are great as well. Anzai did his characters very well. I'm probably forgetting a lot of great ones, too.
And damn, Kurei….. one of the greatest anti-heroes in manga history. His fight with Renge was SO satisfying. There's probably a lot of characters
Another thing Anzai does very well is make really hateable villains. Mokuren and Mikoto are probably two of the sleeziest scumbags I've ever seen in any series.
! That made it all the more sweeter when Kukai became the Oni against Mikoto, freaking demolished her puppet madogu in one punch, and made her piss herself. And then Mokuren stabs her in the gut.
! Then Recca kicks Mokuren's ass, and leaves him in the collapsing building Mori Kouran was a huge scumbag as well, but I actually got some respect for him, starting from when he went through all that pain stepping towards Tendou Jigoku screaming "I ALWAYS GET WHAT I WANT, AND YOU'LL BE NO DIFFERENT!" He's an example of a somewhat one dimensional character done so damn great. He's motivated purely by greed, but it's to such an insane extent, and he's such a twisted man himself, that it makes him an interesting character.
The manga also has some of the coolest, bizarre, and unique powers in any manga I've read. Maybe not quite as unique of bizarre as JoJo or One Piece, but still fun. Highlights being Hiruko's blood madogu, Kadotsu's "gate" madogu..
I really need to re-read it.