That sounds like a fun project, regarding Anomaly i think there are some reasons they prefer doing it the way they do, but its just a guess. But by not relying on the actual renders in Poser they have better control of the style they want. As they can manually paint everything and make it look the same, quickly adjust lighting etc. From the tutorial video its pretty clear that he uses every thinkable way to make the comic get along as fast as possible, whether its modelling stuff themselves, buying varies products or make it in 2D. Which makes kinda sense I think, because if you render some in Poser and some are in 2D, and some objects are bought etc. there is a huge chance that they will look differently depending on who made them and then you also need to match the 3d lighting with the 2D etc. Secondly I think if its a pure 3D render the comic might simply look to "clean", which can be a bit boring I think if you have to read pages after pages. Last if its hand painted it gets the style of you as an artist, which I think is important for any person making a comic book.

So personally for me and don't really have any experience in this area, I prefer photoshop simply because I find it more interesting to look at.