The main attractions here are the presentation of Greek mythology and the Ray Harryhausen led animation, both of which are marvelous for the time and are still admirable to this day. Though there isn't too much to the story or characters, I did enjoy the sense of adventure, and at times found the depiction of scale to be impressive, making you realise just how small the Argonauts are in such a vast mythological world. It felt like a mini-epic, and makes for a good bit of escapism.
Also, I didn't know beforehand that Patrick Troughton was in it, so it was a very nice surprise to see his name in the opening credits, and of course his following appearance as Phineus. Funny considering this was released the same year that Doctor Who premiered, and three years before Patrick's time on the show began.