I'm LDS so for my use Gospel Library is best because it includes the King James Bible as well as the Book of Mormon, etc. it's very easy to use and has many powerful features including a excellent voice narrator. It's free and customizable so you could only download just the bible if that's all you wanted. you wouldn't have to take any of the LDS scriptures if you didn't want them.
I'm a Roman Catholic Christian; and recommend: 1. If you're on a budget, Catholic New American Bible, offered by Greg Fairbrother, for $2.99; or 2. Catholic Bible, offered by Just1Word, Inc., for $7.99, which will also tell you which other translations are approved for use by Catholics, some of which may be free apps offered elsewhere. I hope this helps. Frank