Hi,
I am also interested in ACS Java not because its something that I like but because one of our clients requires us to use it. I have posted some post here or in aD's bboard.
Here are the facts and opinions that I have so far:
1. ACSJ 5.0 is ACSJ 4.7 with tons of bug fix. It does not differ from ACSJ 4.7 or 4.6
2. According to one of the ACSJ persistence layer developer it will take around 3 months to port ACSJ to postgres. porting the create scripts and PDL files.
3. If you are looking for mature OSS CMS solution that is Java based look at mmbase or opencms. I like mmbase better since it looks more flexible, the community is very active and organized.
4. The permission problem is still present in ACSJ 5.0 so permissions are not used in ACSJ production sites but rather using just the workflow for the permissions.
In my opinion stay away from ACSJ if you don't require it because:
1. According the one of aD's developer it offers no real advantage over OpenACS. Maybe only bebop is the real advantage.
2. Look at other Java solutions if you need Java. Why? ACSJ is not really take advantage of Java platform. Too much dependence on Oracle not that portable, does not make use of app server scaling. ACSJ still uses the traditional web farm with one db scaling. Go look at mmbase and see the difference and advantages of using Java. mmbase is also a mature solution.
This are just my opinion and the facts that I got. Some maybe wrong some maybe right. As for me I may be forced to use ACSJ.