Sleazy Fork is available in English.
Can work on almost any webcomic/manga page, preloads 5 or more pages ahead (or behind), navigates via ajax for instant-page-change, lets you use the keyboard, remembers your progress, and it's relatively easy to add new sites
Mangahere and Mangafox does not work?
Webcomic reader no longer works on Mangahere or Mangafox. Is it something about the featured page?