I am writing this at the time when a DVD has been released, and I've worked through about 3/4 of the long series. I was young when the series first aired, and only vaguely remember any of the stories. Strangely the DVD's are labelled "18", and yet it's hard to see why, because certainly the stories contain no swearing or sex, and the violence is restrained, with barely a spot of blood in sight.
Although there are many mystery and suspense TV programmes, especially made in the 60's and 70's, Thriller has many unique points which mark it out as something special, and to be treasured.
Firstly, each show contains completely new characters so it can go in any direction it likes - it can kill off the main character - the bad guys can win or lose. One thing is sure, things are not what they always seem.
Secondly, the programme has its foot planted firmly in reality. Only once in a while does Thriller put a supernatural hat on.
Thirdly, there's long enough in the 65 minutes to develop a full engaging storyline.
Fourthly it's a chance to see some of the great British actors who were working in the 1970's. The one with Helen Mirren is worth looking out for, because she looks so stunning.
It's possible to compare against Hammer House of Mystery and Suspense, but the latter tends to display predictable plots, and once you see where the story is going it goes there - Thriller on the other hand is likely to turn events around, so just when you think you understand what's happening, a new direction is reached, or the final denouement is done in a way you didn't expect.
There are very few lemons in the series, perhaps the occasional sub-part story in the first series.
The only annoying thing is the token American which seems to be in every single story - presumably to make the series attractive to the USA market.