So for example, Clojure has vim-fireplace for an excellent clojure experience. Same thing with Haskell.
Go to where the users are and your life will be easier.
I don't use Syntastic, but haskellmode-vim and ghcmod-vim integrate nicely with ghci, and neco-ghc gives autocompletion.
I don't use tags files or other project-level stuff, the above is good enough to get started.
Also once you have ghcmod-vim you can map a key to tell you the type of an expression:
au FileType haskell nnoremap <buffer> <F12> :GhcModType<CR>
So for example, Clojure has vim-fireplace for an excellent clojure experience. Same thing with Haskell.
Go to where the users are and your life will be easier.