As above, I use Comic Viewer, I liked it because of the ability to use the browser to access comics, but actually I am only reading the comics that I already have at the moment - I love the iPad for reading comics and find that is what I do for the longest period on it - rereading all my comics
. I do not find it a problem to read for long periods - I have not tried reading books/text for long periods of time but the mix of text and images in comics is no problem.
As for Comic Viewer itself, all the problems I was having have been ironed out with the new update - I can import comics through iTunes easily, a wait while they are all unpacked - this can take around 30s per comic though - but you can read the first one and they should all be finished in the background by the time you finish.
Then, the comics are presented nicely on shelves (a la iBooks) you can now stack them together in long boxes and name the box what you want, this keeps it tidy and if you have lots of comics is invaluable.
The reading interface is simple and smooth, tap or swipe to change page, the landscape double pages automatically switch to landscape so to see them you have to switch orientation lock on. The landscape view shows 2 pages at once so has a very comic feel to it, but is too small and I cant be bothered to pinch on every page - it doesn't remember the zoom level and where you are on the page (as Zeal reportedly does). It also has a brightness display which is good for late night reading.
All in all great- was going to change to Zeal but they updated, now I'm not sure if there is a benefit of changing...
NB at present there is no support for PDF, may bother some, and as mentioned before you can turn the "staples" off - they look okay in screen shots but as they are on every page (not just centre) it just looks fake...
http://itunes.apple.com/us/app/comic-viewer/id369599706?mt=8#
FEATURES
* Integrated web browser to download comics over Wi-Fi or 3G
* iPad File Sharing allows you to add comics over USB using your computer
* Full-screen Library lets you browse your collection by cover
* Organize your comics into Stacks, under a single icon
* Automatic rotation of landscape images
* Read in single page portrait, or two-page spread landscape view
* Move back and forth by swiping or tapping the edge of the screen
* Show or hide controls by tapping the center of the page
* Double-tap or pinch to zoom in and out on a page
* Page slider allows you to jump to a specific page
* Automatic bookmarking remembers the last page you read for each comic
REQUIREMENTS
* Apple iPad
* Archives created with ZIP or RAR (files with extension .cbz, .zip, .cbr, or .rar)
* Image file formats of type PNG, JPEG, GIF, BMP, or TIFF
* Image file names numbered in ascending order (e.g. Page1.jpg, Page2.jpg)