Its not about loudness its about good warm unfatiguing sound. Which the Logitech Z313 will produce in spades. Its about correct sound not outright loudness to fill up the room without a soundstage and transparency. If you want loud volume but mindless sound get F&D.
Its how you position a speaker play a very important role in the final sound . For eg I have a Razer MAko as computer speakers and they sounded utter rubbish when the sub was in the middle of my room with two satellites spread 2 feet apart and 1 and a half feet above ground. I moved the sub to a corner and the satellites 5 feet wide and 3 feet high and they started sounding like a different set of speakers altogether!!!

The surface plays a very important role to make your speaker sound good. The Logitech Z313 is brilliant for that kind of money provided the placement is done correctly.
But as I always say sound is subjective do listen before you buy.