It's a hard call. Typically I don't recommend CFDs on commodities through FX brokers because they are more expensive to trade than their underlying future or spot markets.
Then there's the fact that a lot of UK brokers (betting on CFDs is popular there, but note that I say "betting", not trading,) and sleazy brokers off them with high leverage to better drain their client accounts..
But, all that said, Oanda has a nice selection and good pricing on their commodity CFDs.
As far as I see it though, the only advantage a commodity CFD has over their underlying future is exposure/contract sizes that are easier to work with from a risk perspective.