When you use the DLL version of RW Net, there are a few differences compared to the VCL / OCX version:
The DLL version will only allow one network to be loaded at a time because only 1 instance of the network and calculation object is auto-created, when the DLL is initialized. This also means multi-threaded applications are not possible.
You also don't have to mess with both rwnetbase and rwcalc objects. All functions are called directly.
The DLL has built-in dialogs for showing progress, when various functions are called.
RW Net DLL is only supplied with headers for Avenue and MapBasic. If you want to use it with other programming languages, which don't support OCX'es, you will have to translate the headers yourself. The header for MapBasic is then probably the easiest starting point.