It's about as opinionated a subject as anything can be in overclocking. It violates intel specifications and shows no gains that I care about. Lower idle voltage just doesn't matter. As such I've no interest in using it, lower idle voltage is not worth forcing the voltage regulators to work that hard.
The spikes exist, they drop neatly out of fourier analysis and can be viewed on oscilloscopes. No one disputes this. The argument for using it is "the spikes are probably small enough not to matter". The argument against is that it does nothing beneficial and puts spikes through the board that otherwise wouldn't be there. No deaths are convincingly attributed to this, but generally when a cpu (or to a lesser extent motherboard) dies it's been thrashed anyway so this isn't exactly conclusive.