I know that a lot of people (including butchers) frequently 'praise' the porterhouse steak as superior to the T-bone. It's true the width of the tenderloin portion is wider on the porterhouse (technically at least 1.5 inches wide) -- that's great if you're only concerned about the 'size' of the filet portion. But there are two sides to these compound steaks, separated by that transverse process of a lumbar vertebra bone. What about the 'quality' of the loin meat side (strip steak side)?
Usually there's a bit of a tradeoff in the 'quality' of the strip loin portion of the porterhouse compared to strip loin portion of the T-bone.
Here's why. When looking at a complete 'short loin subprimal,' the tenderloin muscle (Psoas Major) gradually increases in diameter from the front of the short loin toward the rear. Hence, T-bone steaks are cut toward the front of the short loin and porterhouse steaks are cut toward the rear of the short loin.
That strip loin portion is not 'homogeneous" from the front of the short loin to the rear. In fact, as you progress toward the rear, there are ribbons of connective tissue that appear woven into the strip loin muscle which are extremely chewy to eat unless cooked for long periods of time. If cooked rare or medium-rare like a typical steak, this gristle component does not have sufficient heat & time to break down. In other words, the texture of the strip loin portion of a porterhouse steak is a little less desirable to me than the texture of the strip loin portion of a T-bone. That's the tradeoff you're giving up for that wider portion of tenderloin on the porterhouse steak. Some people gladly accept that.
My preference is a 'center cut T-bone' which has a decent width of tenderloin but is cut far enough forward on the short loin to have a more uniform strip loin texture without a lot of gristle.
You can see this quality difference in the strip loin portion by looking closely at a raw T-bone vs. a raw porterhouse steak. It's important to distinguish between internal 'marbling' (a good thing) versus ribbons of connective tissue & gristle when observing a raw steak. They both may appear white. But there's more connective tissue (gristle) residing in a porterhouse steak than in a T-bone steak.
In my opinion, 'quality' is more important than 'size,' although I'm well aware that others disagree
