The method to power a microcontroller from one AA-battery outlined in this article seems to work just fine, and as long the uC keeps doing it's thing in respect to generating PWM-pulses and eventually adjusting the duty cycle in respect to the current voltage. It does have a couple of disadvantages, though: first of all, bootstrapping isn't always too easy, depending on the coil and switch used. Secondly, the microcontroller controls its own power supply, which in theory could mean it can blow itself up due to a software bug. Use a zener across the power supply lines if you think you're going to run that risk. Thirdly: Pressing the on-button in the circuit I designed means pulling a large current from the battery, so in theory keeping the button pressed for some time could drain the battery.
There are a few advantages to using this method, too: low part count, no hard-to-find parts, soft power-off, to name a few. The decision to use this circuit is dependant on the advantages outweighing the disadvantages. That, as always, is a choice specific to the particular project, though.