Both never lost to a white boxer. Both lost to a former sparring partner. Both lost while sitting on a stool. Both suffered a broken jaw.
Ali has the best jab in boxing history. Even better than Larry Holmes jab because it was unavoidable.
Both slaughtered Cleveland Williams, but Liston's two victories were more significant since he fought a nearer to prime, healthy Big Cat, whereas Ali fought a guy with a bullet in him...6 years later.