It's absolutely not an alternative to RustEnhanced. Sublime-LSP + Rust-Analyzer complement RustEnhanced, adding Language Server functionality. They don't conflict in any way.
Source: me, a contributor to both RustEnhanced and Sublime-LSP
You’re right, I was mistaken (and too late to edit my comment).
Out of interest, is there a page anywhere explaining the difference between RustEnhanced and Sublime-LSP + Rust Analyzer? I’ve got both installed, but when I enable Sublime-LSP + RustAnalyzer the experience and functionality is different enough that I assumed it was overriding RustEnhanced.
If you’re using Sublime Text 3, it’s essentially an alternative to RustEnhanced[0].
[0] https://github.com/rust-lang/rust-enhanced