Mediacom is terrible.
I moved into a new house a few weeks ago and decided to go with Mediacom because the highest speed Imon offers in my area is 80 mb down / 4 mb up. I ordered Mediacom's 500 mb down / 25 mb up package.
Mediacom was supposed to install my internet on Saturday within a two hour window. After nobody showed up by the end of the time slot, I called customer service who assured me that someone would be out within 30 minutes. Two hours later I received a call that the installation tech had a heat stroke and could not make it until Monday. Five minutes after that I received a call from a different representative who informed me that the installation tech's vehicle broke down and that he could not make it until Monday. I'm pretty sure they were just making up excuses at this point.
During installation on Monday the technician could not get my Docsis 3.1 Modem working (which is required for the higher speed plans). He swapped it out for a different modem, which I found out was only a Docsis 3.0 modem, and incapable of providing the speeds I was paying for. I called up customer service again and they instructed me to go to the local office to exchange out the modem for the correct model. When I arrived at the local office they told me that the phone tech was wrong to send me to them, as they do not carry the Docsis 3.1 modems in local branches. They set up an appointment for a tech to give me the appropriate modem a week and a half later.
At least I still could get internet at reduced speeds, right?.... Unfortunately the following Saturday my internet went out completely and Mediacom insisted that the soonest they could send a tech out was the day that I was supped to get the new modem (the following Thursday). Eventually I got through to somebody who was able to schedule a technician to test the connection from the box to my house on Monday, but this appointment was later pushed to Tuesday. After the tech didn't show up on Tuesday I went to the local office who confirmed that the appointment had been pushed out again to Wednesday. At this point I asked to cancel my service, and the lady working at the front desk didn't apologize or ask what could be done to keep me as a customer, but instead simply shrugged and replied "understandable".
After cancelling my Mediacom service I called Imon, who scheduled a service appointment for a day and a half later. Unlike Mediacom, they actually showed up on time and spent time figuring out the best way to wire my house. I am getting pretty much exactly the speeds that I pay for and the service has been extremely reliable and consistent. Furthermore, their customer service representatives and technicians actually have a clue what is going on and are much more helpful.
TL;DR: Avoid Mediacom at all costs. As a new customer I only had internet service for 5 of the 11 days that I had their service.