What has been the experience of folks who have already been using OpenDJ and OpenAM? Older versions seem free to use but the new releases don\'t seem to be free for use. How
I'll answer your question in two parts:
First as it compares to existing commercial it's actually a very good solution, as it scales, and it's very feature rich. You can go to the site and read all about the features.
The second part of newer version requiring subscription is somewhat wrong. Mainly because there are subscription downloads from forgerock.com. I assume this are for support service contract reasons that one must purchace. If you want to run the latest version just download the nightly builds forgerock.org, and you will be running the latest version. Lastly I will echo Ludovic's comments about the confusion of free.
[Community] - https://forgerock.org/
[Commercial Support] - https://forgerock.com/
PS. I'm in no way associated with forgerock.