I'm starting this topic to get general information, anecdotes, tips, warnings, suggestions, recommendations, ideas from all those out there who have ever implemented a licensing scheme into their application be it a licensing API/SDK or your own proprietary solution.
I've written a small program and have looked at services from Halpeiron, Safe-Net, RLM and others and have recently began implementing one solution into my app. It is a process of learning a new, and from the looks of the documentation, robust SDK that deals with areas of programming I have never explored before. I do 3d math stuff. This SDK deals with network calls, encryption, permissions, XML and really tricky code styles that rely on many many defines, function pointers, and many many funky functions that do obscure things that I can't find in a myriad of books that deal with 3d graphics programming.
What was your experience like?