Stiletto is watchable for three reasons. First it is visibly the product of an industry in transition. The main character is a mixture of James Bond and the Godfather's hit man Luca Brasi: A Sicilian who owes a Mafioso because he once saved his life. He gets regular assignments to kill potential opponents or trial witnesses. But he also lives the life of an international playboy. So we have these typical casino/penthouse/yacht scenes with lounge music and heavily made up, lavishly jeweled dames with mountains of hair topping their heads. On the other hand, the style of the coming Godfather-movies announces itself. One example is the very bizarre, sepia colored title sequence recording the incident in which the hero got indebted to the Mafioso. It has an entirely different style from the rest of the movie, as if it was done by an entirely different crew. There is also a board meeting of the gangster syndicate with an interesting 360 degree pan from the middle of the conference table. The movie soundtrack is also remarkable as it has elements of the sixties and darker, quirkier tones of movie conventions yet to come to full bloom.
Secondly, Stiletto boasts cameos of several people who later became stars or at least well known character actors: an amazingly chubby Roy Scheider as the mobster's lawyer (the physical frame goes well with the part), Charles Durning as a police officer, Raul Julia as a party guest and M. Emmett Walsh as the main character's racing buddy are the ones I recognized. I also thought I spotted Antonio Fargas, but he is not in the IMDb-credits.
Thirdly, the locations are well used. A large part of Stiletto was filmed in Puerto Rico, the final sequences take place in the Conquistador hotel complex, a masterwork of famed architect Morris Lapidus (also designed the Fontainebleau in Miami Beach). The places which represent Sicily are probably also locations in Puerto Rico, the rest of the movie was filmed on the Eastern Seabord and in New York. There is also an interesting meeting place of the O'Neal and Ekland characters, a kind of an open meeting or festival hall with a partly colored glass dome.
Stiletto in many parts resembles a TV production. It is not a really great movie, but for anyone interested in the mentioned three points well worth its time.