The difference between Swiss Steak and Salisbury Steak is that Swiss Steak is made with actual steak as in Swiss Steak is really a steak meat.
While Salisbury Steak really is not steak but is made from ground beef to seem like a regular steak.
The Salisbury Steak is made using ground beef that is shaped into a patty and sold as a steak but really it's a ground beef patty.
But the Swiss Steak is actually the steak and not ground beef.
Both are good but the Salisbury Steak is basically fake steak while the Swiss Steak is actually steak.
They are often confused with each other but they are different.