I have the iPad, and would like to upgrade to the iPad pro if they come down in price a little. I might have to wait until my old iPad wears out, before I can justify such a big purchase. If I was only reading lyric sheets with chords, the iPad size can work out fine, especially if you use the OnSong format. I usually copy and paste lyrics from the web, and insert the chord names in the onSong ap. You can control the font size and transpose at this point and scroll or jump to the bottom of the song when needed. Reading tabs on an iPad "regular" can be a bit difficult, unless you make the fret numbers bold and large in an app like Guitar Pro. For performances, I like to keep things simple and switch to paper (or have it handy), just because the app might decide to crash at just the wrong time. We had one summer performance where an overheated iPad just turned itself off. The tablet is superior in low light situations, and you can turn down the brightness to a comfortable level. In direct sunlight, paper is better.
–Lori