With millions of customers , obviously not everybo...

With millions of customers , obviously not everybody will have a great experience. Mine was excellent minus one star.
I needed service on a private road with a confusing postal address and while initially Optimum said they were not the carrier for that road when applying online, I called, because Optimum is what cable mover said.
The representative (Beverly) went to great length to figure this out, had a field review done, called me back on a Saturday and eventually I got hooked up as promised and almost immediately.
Turns out their service was always there with a great signal, but due to 7 years of nobody living at the house they couldn't tell.
Installer arrived as promised and figured it all out in 45 minutes. Despite everything working right away, he still made sure all pole connections were up to date. Very helpful installer , even dug me out of the snow.
Then comes my one star deduction for trying to get the ordered plan corrected .
An endless loop of voice prompt options, none applying to my problem. Dialing "zero" will not get you the operator to figure out who you should speak to.
That is bad!!!!
Ended up doing an online chat and figured out what has to be done too get my plan corrected.
All in all one should not expect a perfect world, especially in cable.
Just keep going until you get what you want :
PUT UP WITH IMPERFECT HUMANS. (IF YOU CAN SPEAK TO ONE THAT IS:-)

April 5, 2018 Update
Cable industry customer service at its finest (sarcasm), as in confirming bad reviews all cable companies get..
Got overcharged, credited incorrect and now the saga begins:

Website directs one to FAQs or one can chat, so:

1) Chat with Javier, explaining things.
While polite he could only see what I can see on the website and not issue a credit. Somebody will call me within 4 business days.

Yes, if you had you bet money that would not happen: You would have won that bet!

2)Another chat with Javier, who did not remember me, besides my situation being very specific! Maybe Javier is just the chat name showing up and multiple people answer under that name or Javier has a bad memory? Promise to get this to the "escalation team" Somebody will call me within two working days.

Yes, if you had you bet money that would not happen: You would have won that bet!
3) Figured out from a convoluted web layout how to contact Cablevision by e-mail. Clearly everything is set up, so they do not have to talk to you or do anything! E-mails do not allow attachments and generic reply is we'll get back to you within 2 days.

Yes, if you had you bet money that would not happen: You would have won that bet!

4) Decided to call and got Scarlet, who could not understand what I was explaining, but finally got to verify that what I was explaining was correct.
Told her it's my 4th try and that they do seem clueless on how to handle things. Never mind promising replies that never happen.
She promised to accelerate it to the "escalation team" and I would be called within 2 days.

Yes, if you had you bet money that would not happen: You would have won that bet!

All of this over an incorrect charge of $ 79.00 which should have been credited on the first try and a few $;s incorrectly credited.

Initially I was planning to stop by the local office, except I expect that the
reps in that office do not have the authority to issue credits and would djust promise to send it to the "escalation team" and I would get.........

Now I'll try my luck with a letter and I predict I will not get an answer.
Maybe we get lucky and at least get the credits which are due.

In summary, the company is definitely overwhelmed , badly organized in customer support and/or understaffed to take care of even the simplest issues. (Mine is very clear)
They do not even assign a case ID (I asked for one) to keep track of an issue.

For now I would rate customer support as 5 minus stars if available.

On the positive side , the cable connection, wifi etc. work flawlessly.