I had two accounts for a long time, my main on TD and a small secondary on eTrade. I always preferred Ameritrade's format and tools but I liked having some division of funds.
I had completely unacceptable trading issues with eTrade and immediately consolidated into TD. Never looked back.
I started out on Ameritrade, so I'm definitely biased, but I've never had trading problems with them. Knock on wood.
Then again, some stocks are inexplicably restricted on Ameritrade, too. Brokers aren't perfect, yet.