In my experience, both printers can produce excellent B&W prints, bearing in mind that the end result is a combination of the printer/ink set and the paper.
In my view, the Epson may have a slight edge over the Canon because of the Epson’s really good ABW mode, but both printers are capable of producing high-quality B&W prints.
One thing to bear in mind with the Epson that may be relevant for B&W printing is that I have witnessed roller marks in four P5370’s when printing images with meaningful areas of black or very dark grey on cut sheets of PK papers: it is unclear to me if this is an “endemic” issue to the P5370 line or an issue that only affects certain printers. At any rate, even if your printer had the issue, there is a workaround which is to print affected images on roll paper and select the “paper eject rollers/do not use” setting.
Having said all that, if you regularly use roll paper, I think it is an easy choice between the two printers as (once again in my view) pre-cutting sheets from a roll and then feeding them to the Pro 1100 is only an option if you do it sparingly and much less so if you plan on doing it fairly often.
