Hi,
Been browsing e-reader field for few years (yeah no gold) and I can say one thing for sure. It's up to Your eye so go to the store and look at 6 - 7 - 8 - 9 - 10 hah even 13 inches screens. That's all.
I find Kobo Forma screen much clearer/detail wise (just look at the cloud on the upper right) than Libra but still considering second one (color wise mostly? haha). Not sure if it is a matter of 300 ratio only though so forgive me noob talk.
https://ibb.co/311QSZ5
One thing that frustrates me in those 2 are white margins and sides as if cut. Also it isn't original manga page size right??????
Imo the old Onyx Boox i86 screen was perfect for manga size wise but we all know how bad it performed hardware wise.