King Bradley was trained from a young age in all sorts of combat which could easily counter something as rudamentary as alchemy. Even when Edward was shown taking his State Alchemist exam he destroyed the created spear before he knew it. Not to mention he could easily hold his own against any of the other Homonculi without the use of his special eye which I'm not even 100% sure what it does. King Bradley wasn't shown to really have much weakness, and was arguably stronger than Pride due to the amount of fighting he could put up. Sure Ed beat Pride, but that's because he was out of lives which the Philosopher's Stone was giving him and also knew how to beat him and his short ass.
I prefer to use the comparison of Scar and Bradley over Ed and Pride. While Scar won the fight, I don't believe Bradley was in his strongest state either, I believe he was sick or something, which was the only reason Scar won. He also beat Edward and Alphonse together rather easily, albeit before Alphonse got alchemy without the transmutation circle.
Still, I believe Bradley would be able to beat Ed and Al together at full strength. He was able to contest Greed without using his familiar swords, as well as easily beat him with them before Greed was placed into Ling Yao's body, who coincidentally, Ed and Al struggled against.
Again, I'm assuming this is when both parties are at full strength, Bradley with his regenerative Homonculus abilities and Alphonse with alchemy from Truth.
