I used an iPad for my music with both OnSong and ForScore and PDF versions of music I scanned. I found it easy enough to transfer from my Mac to the music app; install the music app of your choice, plug in the iPad to the Mac. I store all my PDF files in a folder on my Mac, to transfer them in bulk, launch iTunes (or it may launch automatically when the iPad is plugged in), click once on the iPad in the left column, then click once on the Apps tab, scroll down to the File Sharing group and click once on the music app you've installed. Click the Add button in the lower right and the Finder window will show. Go to the folder where your PDFs are, highlight all that you want to transfer, click ADD. When it's finished transferring, click Sync. All those songs will be available in the music app, which has it's own steps for placing in the song lists.
You can also simplify it a bit by moving the iTunes window to one side of the screen and the Finder window with the PDFs next to it, then grab all the PDF files and drag them to the music app's File Sharing box.
I recently switched to a large Android tablet, the iPad screen was just too small for me. I found a Hannspree 13.3" 800 x 1280 from Amazon for $199, and now use MobileSheets app, which has a bulk import function. I transfer PDFs from my Mac using Dropbox through my local network. I didn't want to wait for the rumored 12.9" iPad, which I'm sure will be very expensive, I only need the large screen for the music, still use my iPad for everything else.
