When I think of Bible metrics, search
speed is important but nowhere near top on my list. My list for a phone is
here. The relevant bits are:
- Fast navigation. It's far more often that I wish to go to a specific verse than to find all mentions of a specific word.
- Highlighting for the Lord's word.
- References and notations. I like a good authentic translation with good annotations.
- Easy legibility of the screen and font.
I haven't checked any of the Bible apps in that post to see if they work or are needed on the Fire, but you may want
two Bibles; one a book with good navigation and annotations, and one a full text indexed database.