I completely agree on the likability of Sterling Hayden's character Dix in The Asphalt Jungle.
In Rififi I see Tony's (Jean Servais) rescue of Tonio (Dominique Maurin) as being out of character in a good way. Yes, for most of the film Tony is a no-nonsense type of figure, but his gruff and merciless behavior adds a seriousness and danger to the film that I find compelling. Tony's character design seems intentionally opposite the unfocused, more romantic, even sometimes goofy behavior of Mario (Robert Manuel) and Cesar (Jules Dassin).
At the end of each film both Dix and Tony are driving cars in a race against death. Dix wants to get back to the purity of Kentucky. Dying in a field surrounded by horses is cleansing. Tony's fatal decision to rescue the kidnapped Tonio is based on friendship, loyalty and sentiment. His final act is to reunite Tonio with his mother.
Both Dix's and Tony's actions reveal character and are positive, but Dix's goal was known for most of the film, while Tony's action was never a goal early on in the film, rather a reaction to the heist unravelling and a now revealed sense that a child should never be caught up in the work of the underworld.
Dix and Tony are different characters with wildly different backstories. But, there are similarities. They are very capable, involved in a heist, have strong opinions about what is acceptable behavior, and become mortally wounded. I find them very well drawn. Both films are wonderful and fantastic examples of the heist genre.
Thanks for the reminder of Dassin's interview on the DVD.