I’m the developer of Set List Maker (and its big brother, BandHelper). You can either display your existing PDFs, or copy and paste the text into the app; some pros and cons are listed here:
http://www.arlomedia.com/apps/setlistmaker/tutorials/compare_lyrics_documents.html
You can mix and match from song to song, so with my own bands, I started by using my existing library of PDFs, then entered new songs as text directly in the app. Eventually I went back and converted the older songs that had been using PDFs, since the in-app text is more useful for me.
If you do use documents and are debating between PDF and Word, I would say PDF because that renders more accurately across devices. Also, the Android version of my apps can’t display Word files, only PDF (iOS can do both).