Spending on education and training is more effective in the long run - improving productivity
Spending on education and training takes too long to affect the short-run
Spending on education and training may affect inflation in the short-run (increases aggregate demand before it increases aggregate supply)
Spending on education and training needs to be high quality to be effective
If workers' pay rises more than their productivity, costs of production will increase
Spending on infrastructure can be expensive and takes time
Technology / demands have changed by the time infrastructure is complete
Spending on infrastructure has environmental effects
Spending on technology leads to new jobs appearing while some are lost
Not everyone copes well with changes due to technology