In my East York tenure of 3+ years, I have eaten here three times, twice for breakfast and once for lunch.
I think almost all of these kinds of breakfast places can be grouped into two camps. We will use nearby Sarah's as an example.
BTD, in group A, has that same generic taste, selection of menu items, etc. as so many similar places in Toronto. My guess is that very little of their food is made in house. The kitchen is basically taking frozen products and turning them into food. You can taste this in the breakfast potatoes, cornbeef, bread, etc. The reason these places all taste the same is because they all get their supplies from the same places. I think Sysco is one of the big ones. It is a cheap and easy way to run a resturant.
Sarah's, in group B, does things in more of "an old fashioned" way. The food tastes fresher and more individualized. I feel like there are dishes there, even at breakfast, that won't be quite the same anywhere else. Or perhaps they are just using a higher quality supplier. But you get what you pay for and that is why Sarah's is not as inexpensive.
But don't read me wrong--there is nothing wrong with the Terminal Diner. They understand their market and their market is looking for a cheaper fuss free meal. They do a good job with this. I am sure everything here is totally fine, not more and not less. And often this is...well, just fine.
Service was good on all three visits. And the ambiance is a lot of fun.
I don't eat breakfast out often (hardly ever) and when I do, I'm willing to spend a little extra. So, I will usually walk down to Sarah's. But I'll eat here again too. Very recommended if you are near Coxwell Station. Otherwise, you are probably better off finding your own place close to home.