What are the bad sides of Gemini?

As a cryptocurrency enthusiast, I'm curious to know about the potential drawbacks of Gemini, a popular cryptocurrency exchange. Are there any security concerns or instances of hacks in the past? How does Gemini's customer service stack up, and are there any complaints about slow transaction speeds or high fees? Additionally, how does Gemini's trading platform compare to its competitors in terms of user-friendliness and features? Lastly, is there a lack of altcoin support, limiting the diversity of investments available on the platform?