Probably be quite successful, people quite happily believe lies we all should know that given what's happened.
The whole debate on spending is an interesting one.
The facts are no-one actually really knows if one will be more successful if at all.
The same thing happened under Blair if you remember?. You can read conflicting reports about how great it was or how it left us vulnerable to the global economic crisis and make your own minds up.
It's the efficiency of the spending that's the key. You can certainly predict effects they might have but no-one truly knows how it will stimulate the economy, save money in the future etc.... I guess it depends on whether you think the 'risk' is worth it? and whether the electorate is willing to attempt to transform a stagnant economy, stagnant wages, stagnant cost of living and whether you think the tory or labour plans will have the most positive effects.