There are fundamental differences in the two functions:
major one I can think about is that the first lets you draw a portion of the source bitmap, while the latter only draws always the whole source bitmap.
Aside from that, I find the calling convention of al_draw_scaled_rotated_bitmap more comfortable for SCALING only.
I would like to ask if calling the latter with rotation = 0 is roughly equivalent to calling the first one or there are significative perfomance differences (for a large number of calls, likely in every game).
Many thanks for any advice.
EDIT: forgot to mention the different way the two handle coordinates of the destination, but my main concern is performance...so that's not really a point.