For over a year now, I've been posting requests for improvements to the iPad version of BIAB in the Other Programs Wishlist section. Despite generating 2315 views, the response so far has not been sufficient to encourage PG's Development team to act. With those improvements, I think the iPad version would be more popular (chicken and egg problem here?).
I use the iPad version exclusively for performances for two main reasons:
It fits neatly on my music stand next to my sheet music so that
1. the audience can't see it, and
2. I can (without turning my head).
While having BIAB on a laptop next to me would give me more features and flexibility, it would be obvious to the audience that I'm hooked up to a computer, and I'd have to keep turning sideways to view it.
So how about it folks? If we can generate enough interest, I'm sure PG Development will respond with their usual great effort and we'll have a superior performance version of BIAB on our hands.

Cheers! -Alastair