Well, I'd go farther and claim that it would be beneficial to have ArsDigita's involvement. We still have about 50 (not sure of the precise number) programmers involved with programming a version of ACS TCL, can contribute code, and have a vast amount of experience both in the specific architecture (Oracle more than PostGres of course). I think it is beneficial to both parties if the TCL efforts went down one path instead of diverging.
The "use" of OpenACS is a funny thing to describe right now because
the only thing to work with is ArsDigita's version with hooks that will allow you to toggle which database to use. But, given the
strength of the community, it is clear that it will grow from
there.
We've already agreed to use OpenACS as a base for our TCL efforts and to merge back whatever divergents we do for specific client needs.
This is exactly like what we did with AOLServer. We started with what was released, made a aD version after reviewing and putting in changes we needed, and regularly gave our work back. We do that with
all the open source products we use (ant is another example). I thought we were all on the same page that this was good for everyone.