As a Whodunnit its nothing special, but its as good as its peers. Nothing shockingly bad as one of a billion detective shows of the period. As an insight into American Roma its surprisingly good for a movie of 1975. Considering this was the height of Blacksploitation and the like, the Roma are given a fair crack of the whip. All the Gypsy stereotypes are presented as the worst possible types and they attempt to show that not all Roma are criminals by making the hero a 'good Gypsy'.
The hero, Roman Grey, is a charismatic and believable character. Both as a detective and a 'philospher among thieves' as they have tried to paint him. As a character caught between two worlds, an educated man and a virtuous Roma he is easy to identify with and empathise with. And then of course there is all the cultural colour intended to be the hook for the TV show.
All in all, its an acceptable way to spend an hour and a half, it'll educate you a little on how some Roma are. It's just as shame that the TV series it was commissioned to pilot never got of the ground.