First, you have to remember that the most likely people to post negative reviews are people that had issues. And while they may have had issues there are still millions of accounts that are doing just fine.
Second. Square was the company to revolutionize Credit Card processing and bring it to the masses. Before you had to have a credit card processor come out and verify your business and have lots of restrictions, now anyone can open a Credit Card processing account meaning people that have no experience with business legal paperwork, Credit Card processing rules, the fact that chargebacks exist, now have accounts and realize there is more to taking credit cards than just cash.
Third, I can attest to my own experience with Square and three other local businesses that I have setup with Square (and a couple thru our independent Garden center facebook group) that process over $2 million a year with Square and haven't had any difficulties. I've been with Square for 6+ years.
So while there are going to be people that run into issues, some legitimate issues and some from not following the terms of service etc, you have to also remember that for every person that posts a negative review there are 5,000-10,000 users that are charging away smoothly.
