My convert gave me like SBD to Steem at a rate where SBD was treated as worth $0.70. So in theory buying SBD at best gives you an 8 cent advantage per SBD you buy. But the reason it gives this advantage is because if the price of steem immediately plummets when you go to convert, you run the 3.5 day risk. In the past, when conversions worked correctly, SBD would hold 90 cents or more.

So unless you can predict the market ahead of time, it's probably not worth doing SBD convert.