You are talking about two of the PL greats, possibly even transcending that - Schmeichel is often considered top five all time greatest goalies - greatest of all time by quite a few. He was never as dominant as either. He had arguably even greater reflexes than Schmeichel, and both could pull off unbelievable saves, more so than VDS was capable of. At his prime, DDG was also good in one on ones. Schmeichel, however, was also a brilliant shot stopper, but attackers were genuinely scared of him one on one, and he would dominate the box - with one hand if he had to. He also commanded the defense like a (very angry) general. VDS was completely different, but he hardly made mistakes at all - was great at organizing his defense and had this uncanny ability of just being exactly where the shot came. Amazing positional sense, great with both feet and overall a brilliant distributor, especially for his generation of goalies.