Ordered is the classic history-based way of creating parts, and involves storing each step and "playing them back" if edits are made. It is very robust, but sometimes simple changes can be difficult.
Synchronous recognizes all the "intent" of the model *in* the model. It says, "I don't care how it was made, I just want to move these parts". We can provide most all the functionality in the ST paradigm, but we preserve the Ordered workflows for cases which require it. You can *also* do a mixed mode, where the fundemental part is ST, but some of the details like blends are ordered features. This provides the maximum flexibility and power.