我没有用过 vimtex，不过我看到 vimtex 的 Readme 中有描述二者的区别：https://github.com/lervag/vimtex
The main difference between vimtex and LaTeX-Suite (aka vim-latex) is probably that vimtex does not try to implement a full fledged IDE for LaTeX inside Vim. E.g.:
vimtex does not provide a full snippet feature, because this is better handled by UltiSnips or neosnippet or similar snippet engines.
vimtex builds upon Vim principles: It provides text objects for environments, inline math, it provides motions for sections and paragraphs
vimtex uses latexrun or latexmk for compilation with a callback feature to get instant feedback on compilation errors
vimtex is very modular: if you don't like a feature, you can turn it off.