Being like a Mugen is not bad...what they're saying is that some companies copy other brands to save money on development. I can't speak for the Caster car...but the OCM isn't a copy of any other brand. It may have similar features as some...but it is far from a copy.
Saying our buggy is a copy of a Mugen is like saying all cars with c-hub suspension are copies of each other. It just ain't so.