To answer the question of which CBD oil is best, we have to understand the difference between the products: cannabis CBD oil is of course made from Cannabis (marijuana), and it contains high levels of CBD and THC. In fact, the THC can be anywhere from 0.3% all the way up to 30% and beyond. Cannabis oils are normally created to combat different debilitating medical conditions (such as cancer or Multiple Sclerosis), but they are also used for maintaining general wellness.
The major problem with CBD bottles on the open market is that in most cases they will contain levels of THC which are higher than the amount legally allowed to sell. This means that in most states (with only a few exceptions such as California, Colorado and Oregon), THC is currently legally available only as Medical Cannabis, and should be sold only by legit dispensaries that have received proper licensing from the state.
Also, while sheer "popularity" certainly shouldn't account for everything in terms of identifying the quality of a brand's product, there's no denying the fact that the cream always rises to the top of the market competition. In other words, things like product quality, reputation, and overall product value will always separate the reputable organizations from the inferior, low-quality ones. 

After months of visiting doctors and sitting through tests like a human lab rat, it was determined that there was a slight anomaly in the anatomy of my temporal lobe—the part of the brain that controls hearing, speech, and auditory comprehension—which explains why every time I have a seizure, I suddenly don’t understand the English language. Epilepsy can’t be cured, so the only course of action available for me was to take a medication every day for the rest of my life. My neurologist prescribed a few different anti-convulsant medications, but they all made me feel tired, depressed, slow, and unlike myself—until finally, I found one that was slightly better than the rest.
There are many websites claiming that their CBD oils can cure everything. This is not true! Reputable companies extract their CBD oils from specific strains, and remember that each strain has its own unique CBD/THC ratios. Also, some are Sativa and some are Indica; therefore, the oil extracts may work better on some conditions and some individuals than on others. Always read the fine print, and if a company offers a list of medical conditions the CBD oil treats best, just know that it’s completely bogus.