My main complaint is that their software is unstable as a lot of apps written in Java are. I can't keep the options window open for than a few minutes without it getting f***ed up. Of course, I can't just close it and open up a new one. I have to close the entire software. With the current version, I have restart my computer as it won't let me relogin without doing so. Also, the pricing isn't great for options unless you just use smart routing. This typically results in mediocre fills unless it is a market order. If I'm bidding or offering something, I have to pay an extra buck to send it to the most active exchange.
I've been meaning to leave for the last year, I finally am as soon as I pass the Series 7. Although, I will probably keep it open and use as a backup. I would still recommend them, they just don't suit my trading. And that's the point, they can't be all things to all people. Some people are better off going elsewhere, I am.