Mostly make my own with 3 different steaks using a decent sized mincing machine at home and after adding blitzed crackers, eggs and cracked pepper are hand rolled into a ball slightly smaller than a tennis ball and thrown between hands, spinning as doing so to form a tightish ball.
Sometimes I may add some diced onion or small cubes of cheese or garlic...It really depends on what is around that needs using.
Buying out, we've enjoyed the Sainsburys and Aldi Wagyu burger, that if not overcooked, makes for us a decent burger.
The OH prefers the steak burgers to be as we have in France, with the word 'Smashed' not one used in our kitchen