Historically, this issue played out in controversies over such things as the Bank of the United States and the Louisiana Purchase. In the historical context, I am inclined to side with the loose constructionists who wanted to allow the creation of the bank and the purchase of Louisiana.
The US Constitution was and is a short document that is not meant to cover all possible questions. It is more of a statement of general principles (with some specifics) than a complete and detailed guide to what government can and cannot do. Therefore, it would not have been sensible to construe the Constitution strictly. For example, it might well have been hard for the Framers to imagine that a president would ever have the chance to buy land from another country. Therefore, they would not have decided whose power that should fall under.
Because the Framers were trying to create a brief document that would lay out basic rules, they did not go into great detail. Therefore, it was appropriate to follow a loose construction of the document.