Which Profinet protocol stack?

[nctnico]

For an upcoming project I may want to interface with Profinet (that is a PLC communication protocol over ethernet) implemented on a microcontroller.
I have been looking into how to interface with Profinet. There are three options:
- Roll my own Profinet implementation
- Buy a protocol stack
- Buy an interface module.
The option of writing my own Profinet protocol stack doesn't appeal to me because it always takes more time than expected. The advantage of using a readily available protocol stack is that I can also add stuff like a webserver to read the status using a webbrowser and upload new firmware remotely. There are several protocol stacks out there and I'm wondering if anyone has experience with one or more of those.