I know it's been discussed several times, but I think we need to look at it from a different perspective. Instead of comparing MLS to Premiership or La Liga and share a good laugh, we should look at lower levels national leagues that actually have a decent quality; I think it's unfair to compare MLS with Championship or Serie B, simply because MLS is the top league in North America.
Here are my rankings, I would place MLS on the 3rd level. Leagues in the third level often produce UEFA Cup winners, but are not competitive in Champions League; In my opinion, Houston, DC teams of past years could compete for UEFA CUP.
Top level:
Spain
Italy
England
Second Level
Germany
France
Portugal
Third level (examples)
Holland
Greece
Turkey
Best of Eastern Europe (Russia, Ukraine, Serbia, Czech Rep., Romania, etc)
Belgium
MLS
Fourth Level (examples)
Ireland
Norway
Denmark
Sweden
Other Easter European (Bulgaria, Hungary, etc)
Austria
Baltic Countries
Fifth Level (examples)
Albania
Armenia
Moldova
Luxembourg
etc.