I use TD/Ameritrade. Seems fine to me. I don’t often have to speak to customer service so I can’t really address that point, other than they’ve been fine the few times I’ve dealt with them. Everything I need to do I’ve been able to do via the website.
If you want to talk about bad customer service, way back in the day, Q used to use Alex Brown as their stock & espp administrator and those people were outright crooks. Before they had a web interface, you would have to phone in your order. There were several times when I called to place a market order, and it would get filled at the lowest price of the day, even though you could go back and see in the intraday that the lowest point occurred in the morning, before I placed my order.