Aluminum versus Steel Shoes

I'm in the process of switching farriers to a woman with a great deal of shoeing education and years of professional experience. Around here, she is the farrier "to the sport horse stars" and her charge reflects that expertise! I've been using St. Croix Eventers in aluminum for the past two resets. Via phone, the new farrier tells me that she does not like aluminum shoes on endurance horses and asked me why I was using them. I told her lighter weight, therefore less stress on the legs, and that I felt that they were better for shock absorption, thought my horse moved out better in them, etc. She disagrees saying that aluminum gives too much and won't hold it's shape. She also said the weight difference between steel and aluminum is so little when applied to a 1000 pound horse that the advantages of aluminum are minuscule. She also feels that steel is the better shock absorber of the two because it holds it's shape better. She frequently uses a brand of shoe by the name of Kerckhaert's. Sure would appreciate opinions from experienced endurance folks as to aluminum versus steel. Also, anybody use Kerckhaert's? Pros, cons?