The following contains major spoilers for Batman: Beyond the White Knight #4, available now from DC.
In the Batman: White Knight universe, one of the most intriguing aspects has been the Robin lore. The franchise didn't elaborate much on Dick Grayson in the yellow and red suit, starting off with him moving from being Nightwing to a soldier helping Bruce take down threats like Joker and Azrael. However, while the series was coy on his past as the Boy Wonder, Bruce did mention how good he was on the rare occasion.
The recent stories also brought in Jason Todd, this time as a prison warden who left the Robin mantle behind, and who was now tasked with monitoring Bruce in jail. The series didn't dive much into Jason's history either as Gotham's first Robin, other than he was ambitious, until Joker broke him. Still, Bruce respected Jason, praising him as his best student. However, in Batman: Beyond the White Knight #4 (by Sean Gordon Murphy, Dave Stewart and AndWorld Design), fans finally have a definitive answer on which was the best Robin out of the bunch.
Firstly, Jason has to be disqualified from the conversation because as a teen, he got kidnapped by Joker, beaten badly, and then fled Gotham. He had potential, but ended up enrolling in the military and prowled the world taking terrorists out. Even Jason himself admitted he was never physically or mentally cut out to be a Robin.
However, there was one other Robin besides Dick: the new addition in Duke Thomas. Duke took up a new Robin costume after Barbara Gordon confessed she needed him to aid Gotham PD. They didn't trust Dick and his oppressive task force, especially as they were run by Derek Powers. Duke was the only person Barb felt safe with in terms of adding to the arsenal, helping Bruce bring down Terry McGinnis and Powers.
Duke eventually broke into Dick's base to steal info for Barb from her ex, which led to a skirmish between him and Dick. Duke used his arm guard to deflect Dick's bullet before smacking him down with his electric staff. It happened in the blink of an eye, proving Duke was faster, stronger and smarter. In fact, as Duke left Dick on his butt, he gloated how too much time behind the desk made the ex-Nightwing sloppy. He even joked how this was the second whipping Dick got, with the veteran in Bruce beating him senseless when he broke out.
This summed up why Dick recruited Duke in the past, why Barb knew Duke was an ace in the hole, and why Bruce, as much as he didn't want to admit it, was glad to have the hooded Duke as the new Robin. Duke's military acumen was unlike any other, plus with his street smarts, he had a unique sleight of hand that let him see angles no one else did. This, ultimately, left Dick ashamed he got spanked on his own home turf, punctuating who the best Robin was by a mile.