content: Naturally being made by the company that made the PDF standard in the first place Ive had no trouble opening valid PDF files. If I could suggest one improvement for future versions though it would be the ability to delete the resident copies of files that it makes in the app without having to go into the phones settings and delete the apps data entirely. The extra space they use really starts to add up after awhile. Also maybe ease up on beating us over the head with the Liquid feature.