instand1 - 7:36 pm on Oct 16, 2013 (gmt 0)
One big advantage of "broad match" keywords: It can serve as a research tool for good keywords as well as negative keywords.
See results in your account: Keywors > Details > Searchterms >Selected (once you have a reasonable number of clicks). Its not the cheapest way to learn, but it saves time.
In this way you will get faster into it, if your exact keyword does not give enough impressions or its ROI may not be attractive.
Switching off display network: Good for the beginning. Even later: Start a new campaign for trying it out separately: One for search only, one for display only.