Ok, I'll add a further two pence worth on the subject of the stiffness of a power supply.
Firstly, I think it always makes sense to consider the circuit which the power supply will be supplying power to. For example, a 100W power amp might draw only 100mA when it's idling but draw several amps at full tilt. On the other hand, a class A preamp might draw only 10mA - and it will draw only 10mA whether it's idling or at full tilt. So for the preamp there's no point in designing a power supply that will maintain the same voltage at 1mA current drain and 4A current drain because it will never see those variations.
However, although the preamp's current drain is constant 10mA averaged over time its current drain is modulated by the signal it is amplifying. That means looking at "stiffness" slightly differently. The power supply must be able to supply the demands of the preamp's modulated current requirements while staying stable, and that means if the preamp is amplifying a 50Hz signal the current will be modulated at 50Hz, and if the preamp is amplifying a 20kHz signal the current will be modulated at 20kHz. Stiffness at DC isn't really an issue - it's stiffness at audio frequencies that matters.
A crude unregulated supply would be a transformer, rectifier and smoothing capacitor. The obvious "audiophile" approach to improving this would be to simply have a bigger transformer, bigger rectifier and bigger smoothing capacitor, but examining the power supply's output voltage while it feeds a preamp which is amplifying a 10kHz signal might soon show you that you have just spent a lot of money for very little improvement. A much smarter approach would be to add a voltage regulator - the design of which is a topic for another day.

The point I'm trying to make is that it's more useful to consider power supplies not so much as "good" or "bad", but rather "suitable" or "unsuitable" for the circuit they will be paired with. What's good for a power amp isn't necessarily good for a preamp.