Some people rave about it, some people have terrible results, and others are indifferent. I tried it, and my skin was nice, but it wasn't any better than the results I get using my CeraVe hydrating wash.
The key to the oil cleansing method is castor oil, which is what actually cleans the face. From what I've read online, castor oil penetrates the skin deeper than a lot of other cleansing agents. You mix castor oil with other oils in amounts that depend on your skin type. For oily skin, you might want to do 50% castor oil, and adjust it using less castor oil for combination or dry skin. People mix the castor oil with all kinds of different types of oils.
If I had seen some amazing results, I would have stuck with it, but it was mostly a pain in the ass - mixing the oils, rubbing it into my skin for what seemed like forever, then steaming the skin (I would put a hot wash cloth over my face). It did seem to clean my skin and leave it nice and soft, but again, I can get those same results with a much easier routine.
The reviews I hear are also mixed, but I can understand what the benefits would be. However, the actual method and prep for it sounds annoyingly time consuming. I'm good with the face cleansers I already use, haha.
I will say though that I got a sample of Boscia's Makeup Breakup cool cleansing oil and I REALLY like it. It actually removes all of my makeup (even waterproof stuff), and feels neat haha. It rinses off clean, no oily residue. The bonus is obviously that it already comes packaged and you don't have to worry about figuring out how much of which oils to use. I think if you are considering oil cleansing at all, the Boscia is a good place to start.