Overall, Trigun Stampede adheres closely to the manga. Some minor details might differ for the sake of the adaptation's flow and visual presentation, but the core remains the same.
It's quite accurate. The anime version of Trigun Stampede mostly adheres to the manga, with just a few minor differences that don't significantly impact the main plot or character development.
I think it does to a large extent. There might be some minor tweaks here and there, but the core plot and characters are pretty much in line with the manga.
Trigun Stampede takes some liberties compared to the manga. It changes certain story elements and character traits to offer a fresh perspective, but this might not please all manga purists.
One common theme is Vash's struggle with his past. His actions in the past and the consequences they've had on him are often explored. Another theme is his relationships, like his friendship with other characters or potential romantic relationships. His pacifist beliefs are also a big theme, and how he tries to uphold them in different situations.