Chill, I know that he tied with Gol D. Roger and all, but I think that he was stronger than Roger in his prime. Now why would I say something like this?
First of all, Edward Newgate was called ‘Whitebeard’ during the all his pirating days and those of Roger. So that means he probably was an old man when he started pirating, and was past his prime, because I fail to believe a young man would call himself Whitebeard. Secondly, WB told Shanks that he was 100 years too young to tell him what to do; if we take that literally it would mean WB is at least 137 years old, making him 115 when Roger died.
So, Roger was probably in his prime when he was PK, and Whitebeard equalled him as an old man, so my guess is if WB had fought Roger when they were both in their prime, then Newgate would have won.
Discuss.