Trigun is an anime I watched sometime back and find it pretty enjoyable to watch especially since this anime is over 20 years old.
The plot is well planned out and the elements and concepts are well incorporated to make for a more enjoyable story. The adventures that Vash and company go on are both exciting and can be truly dangerous.
The character development is done well and the characters do grow and change depending on the circumstances throughout the story. The interactions between them can also be pretty entertaining and can give you a good show here and there.
The graphics are from 1999 or so and can be considered decent for that timeline but the animations are definitely really good to look at especially all the gun fights!
Overall I would say this is an anime I can recommend to check out if your looking for something a little older or just want something different to try out.
You can find out more at https://myanimelist.net/anime/6/Trigun.