We recently visited and tried the smoked meat at both establishments.
Both were very good but The Main was truly superior. Much more moist, we got "medium" at both places, and much more flavor with more pepper and such. I can't figure out why people think Schwartz's is so much better.
The Main had much better fries too, they tasted like...potatoes! Really really good potatoes.
And the Main had more room around the tables. We have a baby so that mattered to us.
And the wait, well because people flock to Schwartz's (but why??) the wait is not long at The Main so maybe that is a good thing and I should shut up and count my blessings!