I've used Komik/Perfect Viewer/ACV/ComicRack/jcomic on a number of owned devices including SGN/Asus Transformer.
I've also go an ipad that I used to use cloudreader on.
When in bed, if holding the screen really close to my face, whilst lying on side - the SGN and 7.7 are about equivalent for me. In general use though, the 7.7 is the best size for comics. May need to dim brightness in dark environment (eg. long flight) because it can feel a bit like retina burn. The true black makes the comic "float" in the middle of the screen.
Response is very smooth on Perfect Viewer on both cbr and cbz. This is my preferred viewer with preconfigured brightness down/up on the bottom left/right. I set 200ms transitions and 10% swipe tolerance and the thing flies.
I am 6 foot with normal size hands for my height. It's doable, but not super comfortable to hold and swipe with the one hand. I don't use a case/cover. The fact that it's feather-light is a big plus.
Feels almost like the ideal device atm. On flight mode, battery only dropped about 10 percent from 75% on a 20 hr flight. This was on low brightness. Almost constant use.
The Asus Memo might be a better size when it comes out. Will wait and see.