GoodReader – Best PDF reader for iPhone
Ever since I got my iPhone I had been wanting to get a really good PDF reader. Quickly after the launch of the AppStore there were quite a few of them, but none of them seemed to be able to handle a 750 page tech manual that well. For a while though there has been an app called GoodReader, and it just got better.

GoodReader PDF RefLow
GoodReader costs £0.59 and was already able to read really large PDFs with some neat tricks. Now, in version 2.3 they have added a lot more cool options. The coolest one I think is PDF Reflow which will reflow the text in a PDF to be larger and easier to read, without having to do a weird zoom around the page margins. The new version also supports USB file transfer (Mac only) to the iPhone and a load of other new features and optimisations.
Overall I’m extremely happy with this app and it’s one of the few apps for the iPhone that really show what good software engineering is all about. Get it now at discounted price (£0.59) in the App Store.
Cristiano on Tech/Life 
Actually Good Reader supports USB transfer on the PC as well:
http://goodiware.com/gr-man-tr-usb.html#WINDOWS
Awesome, I didn’t know. That’s pretty cool!
Can it read big files which has bookmarks?
Yes it can!
i don’t see the point of spending cpu power (means battery) for pdf reflow when you can just use more appropriate format, “epub”
there are free converters, “calibre” for example, or online http://2epub.com
I think that’s more of a personal interest. Personally I’m too lazy to convert before sending it to my phone. Additionally you need to keep in mind that sometimes the reflow or the conversion doesn’t work (I read a lot of books with code samples that just aren’t readable without the original formatting.) Therefore having the option to revert to the original is a must have for me.
USB File Transfer (this feature is discontinued due to Apple’s demand)
http://goodiware.com/gr-man-tr-usb.html#WINDOWS
sigh..