This kind of bi-modal distribution usually means one of three things. Most often it means the product is crap (Sturgeon's Law: 99% of everything is crap) and th

This kind of bi-modal distribution usually means one of three things. Most often it means the product is crap (Sturgeon's Law: 99% of everything is crap) and the vendor has been buying or posting fake five-star reviews. Occasionally it means the product is really good and a competitor has been buying or posting fake one-star reviews. Even more rarely, it means that the vendor and a competitor are both participating in a fake-review war. You could try looking at both sets of reviews to determine which scenario it is, but the odds are heavily stacked against it being the one that suggests a buy. As galling as it might be to let the miscreants win if that's the case, and to miss out on what's actually a good product, the safe bet is just to move on.