*Head to Head comparison*
A year and a half ago, I'd have told you Burger King and McDonald's were evenly tied for "cheap filling food".
Today, it's McDonald's, since Burger King has downgraded their dollar burger THRICE in under three years.
Double-Cheeseburger -> Buck Double -> Single Stacker -> Bacon Burger (no cheese

)
Now, McDonald's admittedly also downgraded their sandwich once:
Double Cheeseburger -> McDouble
But I can still put two bucks down and have a reasonably filling heart-killing dinner on the way home. Even for taste, I still find the McDouble better than the Big Mac, better than their Angus line, better than the Quarter Pounder and DQP.
As for chicken: The McChicken is a big hit-or-miss with me.
Made correctly, it's crispy hot and fairly tasty for the price. Made incorrectly, it's a tough, over-seasoned piece of shit covered in mayo-spunk.
The Southern Chicken Sammich is a direct knockoff of Chic-Fil-A's, only not QUITE as good.
Which means it's easily the best chicken item on the menu, and lightyears ahead of the Orange Heartburn Submarine BK offers.
What does BK have to keep it out of Tier 2?
They may have downgraded their cheapie burgers, but they have MASSIVELY upgraded their ice cream.
Their strawberry sundae is dirt cheap; at parity with McDonald's price, and it's much better quality no matter what type you get.