Manga Studio is a dedicated "comics" application that's highly compatible with Photoshop (very similar interfaces, the ability to import and export PSD files, etc).
Photoshop CAN do most everything that Manga Studio can do (MS has a few dedicated tools that I wish PS would steal, like the shape tools) but you would need to spend time customizing it and you'd be using a cannon to kill a fly. Manga Studio is built specifically for creating sequences of pages that contain sequences of separated illustrations designed to express a narrative. Right out of the box it helps you to organize pages, create panels that can be focused on as individual drawings, and it contains a dedicated toolset to simulate inking that's unlike anything else I've ever used.
Last but not least, it functions in a dedicated hi-resolution bitmap environment, which is perfect for B&W lineart. There are no shades of grey, everything is either fully black or fully white, allowing for razor-sharp delineation of line. At 600-1200dpi the eyes aren't likely to pick out the jagged edge of the aliased line, but the tools know exactly where that edge lies.
For drawing B&W work, it's my weapon of choice. Generally I use MS to create the line art, and PS for full-color work and final processing prior to client delivery.
Making me consider trying it out. How big of a learning curve would you say is needed to get used to it?