If I am not mistaken, the PCE had problem surviving in the USA because Hudson couldn't release their games there, becasue of a contract with Nintendo or something like that.
And Hudson has made the best games on the console for sure.
I also am pretty sure that the PCE sold more than the Mega-Drive in Japan. I think that the only place where the Mega-Drive had a much bigger number of units sold was in the USA.
Well.. here in Brazil too