I've used them on and off for the better part of two decades or more. You generally need to crank the gain on your receiver a bit for best results, or even uncouple the ground side for weak sigs. During a bad static season they can make the difference between hearing something and hearing nothing.
Before KIPM went to high power, I used to listen to Max via a LOG in the summer months on those marathons. It went from,"What is that weak weird sh!t?" on the dipole to "Ah-ha!"
Some people advise running them on top of moderately high grass and brush, at about a foot, but don't believe it. I've heard marked differences in static levels from near quiet, flat on the ground, to high levels of static as little as 6 or 8 inches above the ground using them at various sites. If you feel like you need more "oomph" uncouple the ground side or add more wire.
I prefer a BOG, Beverage on the ground, after years of messing w/ both as wavelength isn't as big of a deal on HF and there is more directivity, but antennas both are prime static eliminators. The plus with both is you can always straighten the loop out if you've got clue which direction the broadcast is coming from and use it as a BOG, or turn your BOG into a LOG in seconds. It's basically two simple, low cost, effective noise reducing antennas in one.