I'm late into the game, but I just started messing with Manga studio 5's demo. I have to say, I'm VERY happy with the inking tool they have. So much so, I'm going to pick up the digital version of it! Sold! From what little I've dabbled in, it's already much nicer to use for my ink work than sticking with Photoshop, but it can still pop out PSD files. And it's pretty affordable: at less than 50 dollars for the digital copy. Doubly sold!
Sadly, we have a guest staying in my office for a few days, so I won't be able to tear into quite just yet! Up up and away!