I can vouch for IB. I know lots of people have complaints, which are valid, with regards to how long it takes on the phone, or how they auto-liquidate positions, how they calculate margins, and all this other stuff. But if you're looking at Ninja, you're probably going to be trading futures, and in this respect, IB only passes the order along to the exchange so not much can go wrong.
I use Sierra Charts which for me was much better than Ninja, but I guess its a personal choice.
With regards to getting money out, no problem at all for IB. You're allowed one free withdrawal every month and its pretty much just like doing your banking online.
The fact that IB also seems to have higher day trading margins for futures is a good thing cause you don't have to worry about your broker going belly up in some freak market chaos, which can happen, and has happened, with other brokers who have these crazy $400 margins to open a contract.