Should article submissions be formatted in draft format, or in the format of a particular journal? Some journals do not require article submissions to be in any particular format. Would it still be better to try and copy that journals usual format, or use a generic draft format? Would you as an editor or a reviewer prefer one over the other?

For example, many articles use a two column format that is nice and compact for publication, but is a little harder to review and markup - so maybe the reviewers would prefer the article in a single column draft format?

EDIT: I'm specifically asking about journals that state you can use any format you like (for submission), leaving you free to choose whatever will be most convenient for the editors and reviewers. Do you try and still present a "finished product", i.e. format it like it will be if published - or use larger spacing, etc. to make it convenient for review. What would you as a reviewer or editor prefer in the absence of set submission guidelines. Or would you not care in the slightest?
Depends from journal to journal.
There are journals like Decision Support System that require from author to use specific format for initial submission, which btw differs a lot from format of their online publications. It seems to me that format specified in their Guides for Author is designed to ease review process i.e. making side notes and underlining by hand on printed copy.

There are ones like Information Processing and Management, that clearly state they are following "Your Paper Your Way" policy, which in essence: allows you to use any citation style and format for initial submission.

And there are journals, like International Journal of Cooperative Information Systems, that make no such statement, but if you read carefully instructions for authors - they say: that you'll have to apply their template / style / format after being informed on acceptance of your manuscript. 

So, unfortunately, there is no easy answer. It would make a lot of sense if all journals follow "Your Paper Your Way" policy, but it is not the case. Many times, you are left in uncertainty due lack of explicit instruction on this.