PDF Viewer, that is the name of the app, is a good app to read PDF files on Android or Cyanogenmod. If you search the Play Store, there are just too many PDF reader apps and all virtually indistinguishable from each other and almost all of them are crappy in different ways. PDF Reader by Ivan Ivanenko is slow and shows ads. Adobe Reader is extremely slow.
PDF Viewer is a fork of EBookDroid, which used to be my favorite app to read PDFs on Android. EBookDroid had become overloaded with features and this fork removes a lot of the useless cruft from it. Other than PDF, it can also handle DjVu, CBR, CBZ and other comic book formats. The source code of PDF Viewer is available on Github here.
Possibly the most important feature I like in PDF Viewer, and in EBookDroid too, is the auto-crop of pages. This crops the content on a page to the bounding box of the textual content in it. This makes the best use of the precious screen real estate on smartphones and tablets.
Tried with: PDF Viewer 1.1, Cyanogenmod 10.2 and Nook Color