Add rationale for preferring http_archive over git_repository.
Fixes
Closes
@@ -307,7 +307,16 @@ bootstrap test.
### Repository rules
Prefer [`http_archive`](repo/http.html#http_archive) to `git_repository` and
-`new_git_repository`.
+`new_git_repository`. The reasons are:
+
+* Git repository rules depend on system `git(1)` whereas the HTTP downloader is built
+ into Bazel and has no system dependencies.
+* `http_archive` supports a list of `urls` as mirrors, and `git_repository` supports only
+ a single `remote`.
+* `http_archive` works with the [repository cache](guide.html#repository-cache), but not
+ `git_repository`. See
+ [#5116](https://github.com/bazelbuild/bazel/issues/5116) for more information.
+
Do not use `bind()`. See "[Consider removing
bind](https://github.com/bazelbuild/bazel/issues/1952)" for a long discussion of its issues and
