Suchet told the Radio Times (via the Independent) that he’s made a specific point to avoid seeing Kenneth Branagh’s version simply because everybody wants to know what he thinks, and he doesn’t want to say anything bad.
David Suchet has the longest tenure as Poirot, playing the character in a collection of TV episodes and TV movies beginning in 1989 and running until 2013.
As such, it’s probably his face more than any other that modern audiences associate with the character of Hercule Poirot.
However, it turns out the most prolific Poirot has never seen the newest incarnation.