I have not had a great deal of luck with rarer Annonaceae seeds, either. I chalk that up to a relative lack of growing experience and the individual germination requirements of different species.
But, perhaps one of the reasons that many people have poor germination rates with rare Annonas is because we are not providing something that the seeds get when germinating in their natural environment. Or, perhaps some Annona species just naturally have better germination rates than others. For instance, I have read several times on this forum about the hoops that people have to jump through to get decent germination rates for Ilama, but I ordered a packet of four Annona reticulata (custard apple) seeds from Trade Winds a couple of years ago and got a 100% germination rate without really knowing what I was doing.
When talking about germinating rare Annonaceae seeds, I am over the moon at the moment, though. I finally got an Uvaria rufa seed to germinate last week.