I liked David Suchet as Poirot in tv series at least - can imagine him, all around, as much more of a Beligan Detective, much better portrayal of Poirot’s character per Christie’s novels about him. Ustinov wasn’t the right actor for this - he would’ve done better were Poirot a Russian Bear, lol.
David Suchet totally defines Poirot as far as I’m concerned. My wife and I have enjoyed every one of his mysteries.