If it was me i would pulse a compound which i have already used in a regular cycle so that you can tell how effective pulsing is for you as far as gains/sides/shutdown/etc. If you have already used each of these before then i would pulse the one which gave you the best gains/results. I guess it also depends on what your goals are for this cycle.
If you are going for "Solid Gains" i would say that SD is your best option considering the water retention you will get with pp and dbol. On the other hand i do not personally pretend to know if that water retention is reduced at all when pulsing one of these two as opposed to running it straight.