This is a fantastic novel.
Despite it's age, it is wonderfully timeless. The sudden loss of all modern technologies due to an uncertain disaster creates a period-neutral story. The premise, that society is ended when a strange atmospheric phenomenon leaves the world blind - a world in which 'genetically modified' (or hybrid plant as it is presented in the novel itself), carnivorous, walking plant acts as the main antagonist - Is very compelling.
It is also quite forward thinking. Even when the lead female is presented in a stereoypical fashion, it is addressed later when she says how shocked she was at herself for reacting so, despite considering herself a modern woman, and in quick character development hardens herself rapidly. The young girl that is later adopted is also very modern - she becomes the triffid killer of the group in an act of vengeance for the death of her family.
That said, it is of it's age, so readers used to more modern literature may find the characters somewhat archaic. But, I feel that Wyndam deserves credit for his forward thinking depiction of female characters.
The lead character is presented well - not perfect or entirely heroic, but quite realistic. It helps make the story feel real. It feels like a genuine, authentic first hand account.
There are plenty of scenes both heart wrenching and disturbing, and thrilling and exciting. A fantastic tale, and excellently written.