Even without footage of him at his peak, it's clear that Pep was a defensive wizard and arguably the best pure boxer that ever lived. He was certainly the greatest featherweight of all time and you'd pretty much have to ignore his fights before 1948 and the Saddler series to think much differently. His first featherweight reign is the best in that division's history. On top of all that, he holds one of the most astonishing records in boxing history of 134-1-1 fighting during his prime years of the 40s - his only defeat before Saddler coming at lightweight against world champ Sammy Angott. I have him at no. 3 p4p all time in my own list behind only Henry Armstrong and Sugar Ray Robinson.
IMO, Pep was the best "pure" boxer of all time regardless of the weight class. What set him apart was his smooth footwork. He could change directions like no fighter I have ever seen. It was like his feet were made of ball bearings. And, of course, he combined this with unbelievable hand speed and a complete assortment of punches which he could deliver from any angle. It took a fearless, daring, long-limbed, speedy, relentless, and intrepid walk-in fighter like Saddler to defeat him. I can't bring to mind any other featherweight in history who could have done it.