If you want impeccably clean and precise lines, the pen tool is your only choice. Having said that, most (all?) people who actually* ink can't do so with that level of precision. If you want that 'inked' look, I think you best bet is a tablet and anywhere between 300 and 600 dpi for your intended medium. Oh, and custom brushes. At any rate, this is looking good, though I would recommend repathing some of your lines rather than adding extra ones, or playing around with your brushes and using different ones to best fit the direction of each stroke's path. Keep working at it!
*By this I mean on traditional media.