What is the verdict nowadays between ATF flush using a machine vs drain and fill. I was always taught that drain and fill is the only (safe/best) way to change ATF fluid and to avoid using a macing to do a full flush. To me it seems like true car enthusiasts that like to do their own maintenance strongly discourage using a ATF machine to do a full flush while mechanics / shop owners say using a machine is totally fine and most shops do a full flush with a machine. Maybe the modern cars are totally fine with using a machine? I do see a benefit using a machine since you get completely fresh fluid but what are the cons?