I am looking for a good app to read PDF books (mostly tech documentation) on iPhone 4. The main feature I need is continuous page viewing that allows to fix zoom level and horizontal positioning. Many documents have useless empty margins to the left and right of text, so I want to zoom and center them so text takes up full width of iPhone's screen and then simply scroll through the document. I checked out some free aps and found PDFReaderLite that can do continuous viewing, but it is very slow and it's rendering quality is not best. What else is suitable for my requirements? Maybe there's something good among paid PDF apps?