I own several of these boards. I have a couple like the one in the above Ebay link and I have some that come with 3 potentiometers and are setup as a constant current regulator. The caps on all the ones I have are 220µF 35V for input and output. I have tested them with my oscilloscope and they have peak to peak voltage of 120mV with no load and about 400mV with a 2A load (tested it with some big cement resistors). I personally would not use them to power a micro controller unless the load is very low. When you are drawing +1A from the regulator it will heat up the small PCB and potentiometer. This will change the resistance of the potentiometer resulting in a different output voltage. I prefer a fixed voltage regulator to power a mcu. I have made pcb's with LM2576 and the LM2596 5V versions to power Atmega's. I quite like these old switch mode regulators as they are cheap and easy to find and most importantly much more energy efficient then linear regulators. Something worth considering when you are using batteries.
I have one pcb (constant regulator one) that I use to drive 2 3W leds. I have it setup so it gives about 600mA, has been working for more then 6 months.