As much as I hated that storyline, "Inside Out" is one of my favorite episodes of the show. I loved Darla's portrayal in that...felt like a fitting final (non-flashback) appearance for her. I know it's kind of ambiguous as to whether or not that was the "real" Darla, but I've always liked the idea that it was, and that after her act of pure love/self-sacrifice, she ended up unequivocally on the side of good.
That said, I hated Vincent Kartheiser as Connor. Whenever I'm watching it, I can't help but think that I could have really enjoyed this character if played by a different actor. On paper, he's totally fascinating to me. But Kartheiser's performance makes him as obnoxious as possible. At points where I felt like he was supposed to be coming across as this weary, tortured soul, he just came across as a brat. There are just so many times I felt like I knew exactly what the writers were going for, but Kartheiser wasn't selling it. I later ended up loving him in his role on Mad Men, so I don't hate him as an actor or anything, but yeah. Just a total miscast for me.