I read manga on my kobo elipsa 2e (10" 227 PPI, 1404 x 1872 resolution) often and find the experience quite good. I specifically got that e-reader since it has a big e-ink screen. Manga is mostly black and white anyway and the color pages get shown in grayscale, that works relatively well. I suppose traditional comics also work well since they have black text on white background the color to grayscale may cover some detail but should definitely be readable. most color comics and manga are printed in 300 PPI.