Just to follow up - I spent some time digging through the app store and I found "Pulp Reader" which does a really nice job. You can create folders for series, it keeps track of what you've read, you can pinch or double tap to zoom, there's no load time when switching pages, etc. It's working for my needs and most importantly, it's FREE! There's so much out there to read...
The Walking Dead is great so far by the way - I'm 4 issues in and I can already tell it is going to be better then the TV show (and I love the show).