Its really the big ISPs (Comcast, Verizon, etc) who would be benefiting. What they would theoretically be able to do would be to show preference to some sites while placing others on a lower level of priority. For example, if you have Verizon internet and you decide to visit the site of a competitor to check their rates or potentially change service, they could slow down your access to the site, charge additional fees, or even block you altogether. Companies like Facebook, Google, etc don't want this because they don't want another company potentially controlling their users access to their sites. If for example Facebook were to get onto Verizon's bad side, either because they became a competitor or otherwise, Verizon could affect their users ability to access the site by slowing it way down, charging additional fees, etc. Internet Service companies of course love this because it gives them a monopoly over the internet. Companies dependent on the internet hate this for the reasons I just mentioned. Bottom line doing away with net neutrality is great if you are a Internet Service Provider executive, not so great for everyone else with an internet connection.