Filtered means that it is good for sensitive IC's as it will provide the most accurate selected voltage possible. This is accomplished by using filter/bypass/decoupling capacitors on the power rails to reduce noise. This power supply can source power from a range of power supplies within 7-14 volts @ 500ma. The lm317 can sink more than 500ma of current but at the sacrifice of having to use a lower voltage, this is because the LM317 has a max rating of 3watts total. Sinking 1.5 watts of power uses a fair size heat sink so if you want to have more power running though it you may want to move to a larger Voltage regulator.
This power supply is not suited (or needed) to power standard MCU's like the arduino uno or mega. It works great with a few tweaks to power a stand alone or breadboarded ATMEGA328 though, because the power is filtered and you have a nice easy way to adapt it to the same sources the standard arduino's use. Just beware that the ATMEGA328 is capable of drawing up to 560ma with just it's digital pins and this will stress the heck out of the power supply.