If black & white is most important, I would humbly suggest looking first at HP's large format Z3200 printers. First, HP's black/grey inks are absolutely neutral, and in 'straight' BW prints the driver uses no color inks.
Second, it's got a visibly darker D-max on matte/cotton rag papers than either Epson or Canon printers. Enough so that cotton rag papers become more appealing for your black & white work, avoiding the annoying reflections or metamerism you get with glossier papers.
Third, HP's black & white mode is more sophisticated than either HP's or Canon's. It permits you to make the print tone warmer/cooler/lighter/darker using an interactive control that I find a lot more intuitive than Epson's ABW or Canon's iPF driver. There's no true print preview, but it's still quite usable.
Fourth, all black/grey inks are available all the time without any ink-wasting swaps.
All these features to my mind make it worth putting up with the HP's flaky driver, finicky paper handling and fragile mechanics.