Oanda is registered with the CFTC and the NFA according to the bottom of their website:
“OANDA Corporation is a registered Futures Commission Merchant and Retail Foreign Exchange Dealer with the Commodity Futures Trading Commission and is a member of the National Futures Association. No: 0325821. More Information is available using the NFA Basic resource.”
I have accounts with both them and Forex.com and preferred them over Forex.com for trading conditions. I have not yet opened an account on Trading.com yet to compare.