I called the Oanda's sales dept. and waited 10 mins, then the (end of call) auto survey came in and disconnected me. I guess they don't want the sale. Then I called again, and finally got through.

On the 2nd call, I was educated by a sales rep from Oanda, he gave me an example: that if you open a premium account the spread will be reduced by 0.2, and Margin level is 50% close out.

So for a $20,000 deposit, in my opinion, it's not worth it when other brokers are providing the same spread or less.