Reekie, you know I'm playing devil's advocate here. How does one compare then?
The problem here is that the Scottish game has over 100 years of history and the MLS has 11 (including the year we're in).
I will say this and I doubt anyone can argue against it. The game has come miles on this side of the Atlantic since the MLS began and it will continue to improve as it goes. The level of play in the league can only partially be compared. Even the Everton guys who played at Anderson's Testimonial game were saying the scottish game is different than their style that they are used to. We can definitely agree that the game played in La Liga is different from the SPL. The Brazilians? Football on another planet... I can go on. I believe the MLS has a different style again. Perhaps a little more rough around the edges as the talent pool is improving but I would stick Toronto FC, FC Dallas, and Houston Dynamo out against the Falkirks, ICTs, and Dundee Utds. any week and expect to see a match.
The only way to prove it? Try it. Test the theory. OK Open Invite to SPL clubs for their Preseason Tours.