You can't go wrong with either.
Main differences being business class is offered in AV and none in LAN. The sights out the window anyways between LIM-CUZ are so good I'd rather have a window seat sitting on a bucket than be on an aisle seat in business class for one hour.
Get a seat on the left hand side (facing forward, left shoulder against window) flying LIM-CUZ for the best views of the mountains, the reverse, for CUZ-LIM on the right hand side.
Avianca only has like 1 or 2 flights to work as connectors for their long hauls out of Lima, so tend to stick to schedules unless there is a weather related or ATC delay. LAN has a strong domestic network so has more frequent shuffling of flight numbers and times.