When I started doing commercial illustration work I ditched working with pencil and paper pretty fast. In the end the decision came down to speed and precision, given the nature of how my work looks, clients can get quite specific about how they want certain areas to look, this week I’ve drawn about 5 possible variations of a guy’s chin, which would be a nightmare with pencil and paper.
Also clients need the files in digital formats anyway so working with digital from the get-go skips a lot of steps.
I don’t work in vector, I work with raster-based(pixel) images in a program called Manga Studio, you should really give it a try, it’s really cheap and far better for doing black and white drawing than Photoshop.
You need to have a Wacom Tablet though, there’s no discernible difference for me between the Intuos 3 and the 4, I use an 8x10”. You can get an Intuos 3 on ebay for pretty cheap nowadays.
My issue with vector is that I’ve never been able to make it work fast enough and retain the hand-drawn inconsistencies in linework, it’s always a little too perfect. With Manga Studio when you lay a line down, you need to commit to than line, or undo it completely.
I only use photoshop for playing around with different colours and adding textures but the colour layers are drawn in Manga Studio.
If work needs to be blown up really big, I live trace the imagery in Illustrator using these settings which have worked really well:
Hope this helps!