I just spent a couple of months researching this before making my decision. I believe that folks advocating a deep sand bed are correct and the benefits significantly outway the risks. The sulfer issue (while valid) seems be a case of exagerated risk.
I also think you get out of each solution what you are willing to put into it and though there are many benefits to DSB you still need to understand what you're doing and be willing to make a commitment towards your tank. It is NOT a silver bullet that solves all your tanks ills, though it is sometimes presented as such.
Good luck with the change, If you do go with a DSB I'd go a little deeper than 4" if you can. More helps.