In my opinion, the way to go with an A5 is to do the memory mod (it really helps, and is pretty easy!), and then set it pretty tight. If it's loose, it tends to get spongy and not handle corner cutting very well. It works best when it's fairly tight. It has become my feet-solving cube since I switched to a GuHong; GuHongs are terrible for feet solving, and the A5 is the best I've ever tried for feet solving.
I know that Haiyan set his memory cubes just as tight as I set my A5s; I actually set my A5s by matching the tension to my daughter Marie's memory cube.