I recommend
CME website has good service, which shows quotes for various futures and even with leveled 2.
Especially those, who trades forex, can compare in real time what is the price of currency futures, to compare with the spot prices of their DC. Link , which I give, shows futures and forward points. So it is desirable, so that your spot from the provider is as close as possible to these prices and quotes move without delays in the right direction.