I have four Presonus E8 speakers in surround configuration along with a Temblor 10 subwoofer. My music room is 26' x 18' x 7.5', fully carpeted. I use the Caen, Salisbury, Rotterdam (main organ) and Stade sample sets, and have been using this setup for 16 months.I am very pleased with the Presonus speakers, purchased from B&H, and would go for this setup again with no hesitation.
I auditioned the E8 and E5 speakers locally before purchasing, and thought the E5's were perhaps more more pleasant and neutral sounding than the E8's, but since the E8's were on sale and less expensive at the time that E5's, and keeping the size of my room in mind, I went for the E8's. I listened to Yamaha, JBLand Mackie monitors at the same time and much preferred the sound of the Presonus, both E5 and E8. Transients seemed clearer and the sound less colored.
I suspect the E5's would have been adequate, as the E8's are plenty loud. The Temblor 10 likewise is barely idling and will rattle everything in the room!