SamuraiBlue
Captain
To make that claim you'll have to do an apple to apple comparison.No one is saying the Dreamliner and the A350 is a copy of each other although they probably have closer specs than that between the ARJ21 (with its super critical wing design) and its contemporary equivalent, not to mention the DC-9.
The ARJ-21 is incomparable to the DC-9 since the latter wouldn't be able to operate in the kind of conditions that the ARJ-21 is designed for.
Just to make things clear, I am only playing the devil's advocate since I have nothing for nor against it.
For the record I really do not know how successful the MRJ will be either.
It may have a better chance since they are going for US and EU certifications but I believe it is over weight against the US pilot's union regulations at the moment placing it in a difficult position at it's current status in the US.