Interesting to read thoughts from people who have read the books, which I haven't. I started out dismayed at the lack of charisma in both Dickie and Tom despite the very charming actors playing them. Tom seems so obviously creepy and unsettling that I couldn't understand how anyone would let him into their house let alone grant him the sort of trust that Dickie does. Dickie lacks any sort of appeal and seemed a bored and boring kind of man.
Like other posters I missed the glamour of the film and wondered why there was no spark between any of them.
I persevered, though, and started to enjoy the series for its good / great points: the wonderful tension, the very beautiful cinematography. The fantastic supporting cast of Italians. You could freeze frame at almost any point and be delighted by the lighting and composition. The slow burn horror of Ripley as a remorseless sociopath.
I think he's wonderfully portrayed now I have seen the whole series. It still begs the question why do people trust him? I think, though, we see almost everyone treat him with some level of mistrust - they all know to some extent something is not right. The only exception is Dickie (at first) and I wonder if that's part of Dickie's characterisation here. As others have said, he's hopeless, talentless, bored and without ambition. He's not that into his relationship with Marge. He only seems to have one other friend, and it's Freddie. Tom is someone new to amuse him. Perhaps a friendship with someone who dresses up in his clothes and steals from him, initially seems better than an endless life of bored luxury and failed art?
Another question for me is why does Marge seem to suddenly warm to Tom when she comes to Venice? I didn't understand the change in their relationship at all.
I also wondered if Mr Greenleaf had been initially looking for a different Tom Ripley to help him? And Tom just took the opportunity offered?
I'm glad I persevered; I enjoyed it very much once I stopped comparing it to the film and accepted it as a new entity.