besides that futures are centralized ecns at chicago and spot is none centralized.
and besides the time difference of operations.
please don't explain how its derived from the forward price etc..

Answer
There's just a difference in the premium, like in S&P futures vs index.

I've gotten better fills in the futures, especially when trading the reports, because futures are regulated by somebody and they can't rape you as easily, I suppose.

Liquidity is excellent in the futures, just can't get that insane 100:1 leverage.

How is Currency Futures Trading different from Forex Trading?

Answer
From what I can tell, forex trading is conducted with $100,000 dollar blocks in the spot market, whereas futures currency trading is done with $100,000 futures contracts for futures delivery or acceptance.

Also, forex trading uses much higher leverage. like 400:1, whereas futures is more like 10:1 or 20:1.

Also, forex brokers will charge you based on a point spread. So they take money out of your trade based on market conditions. Whereas futures brokers will only charge you a straight commission rate. Thus making it more clear, transparent, and business like.

Also, forex brokers only let you trade currencies. Whereas futures brokers let you trade currencies as well as other futures products.

From what I've learned, forex brokers have a much higher incidence of shady behaviour and the industry is less regulated than futures. No banks or financial institutions do forex transactions, all major businesses use futures.

There are a lot of forex "bucket shops". This means that they scam you. That is not to say that all forex brokers are "bucket shops" or scammers, but a lot of them are.

If you want to trade currencies, I strongly recommend that you do it through the futures, rather than through forex.