i use the market exchange in the upper right on the menu bar.. But i'm not converting it over yet because the ratio has jumped too high... a week about i was getting 2.5 SP for each sbd... now its half as many... so i'm just using @bumper with every sbd until the ratio comes back down (ideally 3 SP per sbd)... You can also see the return on each bumper vote through your www.steemworld.org/@sunsquall page... when the activity happens bumper will send you a notice and you can see how much you earn. If they give you 3x in upvote for the amount you paid in sbd, it is a winner for sure (means you will get back your sbd you paid them, plus keep a little more and all the s p you are paid. The only issue with doing this is if you like the exchange ration of STEEM to sbd. I don't, so I'm just rolling my sbd until I get a price I like.

I know this is wordy, so I hope it helps... if you have any questions, let me know.