Sure...

Stackage: curated sets of packages that are known to work together.

LTS Haskell: Stackage + pinning to a GHC version + seperating non-breaking upgrades (minor LTS version increases) from breaking ones (major increases).

SSL downloading.

Stack: also downloading/building of GHC if it does not exists, understands mega-repo's (many packages in one git repo), eases working with shared local pools of packages, eases working with dependencies that are not in Stackage/LTS, and more that I probably forget.

A more detailed explanation of the merits of Stack can be found in this video: http://begriffs.com/posts/2015-06-22-haskell-stack-build-too...