Like an article I read said, the way Congress has been bickering with itself, if using the 14th works, Obama could become a hero to the voters. The man who finally stepped in and solved the debt ceiling crisis (at least temporarily).
It does assume the new bonds are demanded with a similar interest rate as now. But, if so, Obama can say he saved the country, even the world, from an economic crisis while the partisanship in Congress was letting the country down. This gives him a huge running point to use for next year, especially if he spends all that time working out a spending solution.
Technically Congress could try an impeach him for using the 14th, even though he has the right to do so since he's faced with two contradictory mandates, but even if the House did vote to impeach, the Democrat controlled Senate wouldn't vote to convict.