If you are trying to decide which trading platform to start using out of cTrader and NinjaTrader then we can help you make the right choice. It is now possible to trade with cTrader and NinjaTrader at the same time while using the same cTrader broker.
You can now open a trade with NinjaTrader and close the same trade with cTrader as they will both be connected to your cTrader broker. 
You can now open a trade with NinjaTrader and close the same trade with cTrader as they will both be connected to your cTrader broker.