Is there a better Drupal 7 distribution that I can start with, for an enterprise website which require to have workflow support?
Note: I don't know what you mean by "better", and also I don't know what you are comparing to.
NodeStream is my employers distribution. We base nearly all of project off it, and we try to keep much of our work in the open, to ensure that everyone can use it. We have support for the Workbench module and its workflow.
There was a presentation about how we work with NodeStream and built on top of it during the Barcelona devdays 2012, but as far as I can tell, no videos have been posted from there yet, so I can't link to it.
The problem with using a pre-defined workflow is that every organization is different. Some people need draft/pending/published, but want their own role names. Some people need multiple roles that can bypass different steps. Some people need to worry about moving backward through the workflow, while others don't. Some people need additional states, rather than the standard draft/pending/published.
My recommendation is to pick the distribution that works best for you, and then add on the Workbench module, and one or more of the related modules like Workbench Moderation and Workbench Access. Personally, I find this much easier to configure than Workflow. You should be able to get a basic workflow going in an hour or two.