I'm torn between IDW and 23K.
IDW because he actually gets sh!t done for the most part and has a lot more rounding to his story, especially in that he's basically just a puppet for a witch with daddy issues. A puppet that was putty in her hands. He's someone who wants control of his own life - something that he's pretty much never had. Especially when, all things considered, his life
isn't his own. He's a reincarnation of another man, and just not any man, but his father's sworn enemy.
23K almost had something interesting with Shredder as an Utrom, but it fell flat on its face by the show's utter black and white morals and refusal to hear out another side's perspective on certain events. And this basically
just sums up where a lot of those issues could have been fixed. We could have had someone calling out on the 23K Utroms for having some frankly susicious activity (as was finally revealed in vol 4 of Mirage), but nope! Gotta have a Napoleon Complex and take over all the things with no real reason for it.
...Huh...yeah with that said, I'm going to go with IDW. It's using its potential where 23K squandered it on screaming and unclear motivations.