O modelo estoniano (New York Times)

Estonia...is not like other European countries....Estonia became the first country to adopt [a flat tax] in 1994, as part of a broader strategy to transform itself from an obscure Soviet republic into a plugged-in member of the global information economy.

...the plan is working. Estonia's economic growth was nearly 11 percent in the last quarter - the second fastest in Europe, after Latvia...

..."Everybody dreams about a society with no inequality," Prime Minister Ansip said. "But the best policy is to have a strongly growing economy. With more prosperity we can increase social benefits."

...not everybody loves the status quo...Edgar Savisaar [A prime minister of Estonia under Soviet rule], is among those who believe that the flat tax has deepened class differences...Mr. Savisaar now leads a popular center-left party, which is in a shaky coalition with Mr. Ansip.

[Fonte]

O modelo português conseguiu obter maiores niveis de desigualdade com um sistema de impostos progressivos...e o crescimento económico é ligeiramente inferior...