For my opinions, it's based on a couple different things. 1) Atmosphere 2) Quality 3) Attractions and 4) My insterest in the country. You have to kind of put your interest in there, because it's pretty much what sways your mind.
Top Tier- Mexico, Norway, France
Mexico has great atmosphere along with a solid ride. My interest level is somewhat high for the country. Norway has a solid atmosphere and a great ride in Maelstrom. Again, my interest level is somewhat high. France has a great atmosphere and a decent attraction. My interest level is very high for France.
Good, Solid Countries- United Kingdom, Canada, Japan, Germany, China
The UK has above average atmosphere and has great quality, however it lacks attractions. Canada has a decent attraction, great atmosphere and the quality is very good. My interest level is above average for Canada. Japan has great atmosphere, great quality, but lacks attractions. My interest level is average for this country. Germany is the same as Japan for me. China is the same as Canada.
Average Countries- Italy, American Adventure, Morocco
Italy has solid atmosphere and quality. It lacks attractions and my interest level is above average. The American Adventure has decent quality, average atmosphere and slightly above average attractions. Morocco has good atmosphere and quality, but lacks attractions. My interest level is average for this country.
That's my evaluation of all the pavilions. I didn't count the Outpost as a pavilion, but if I did it would be considered below average. Other than that, there are no bad countries.