Dear Philip,
Checkout Ohloh for some statistics about the development of the OpenACS code base: http://www.ohloh.net/p/3877
About two years ago, we did a more detailed analysis of the OpenACS developer community, which was published as an article:
Neophytos Demetriou, Stefan Koch and Gustaf Neumann: The Development of the OpenACS Community, in: Miltiadis Lytra and Ambjörn Naeve (ed) , Open Source for Knowledge and Learning Management: Strategies Beyond Tools, Idea Group Publishing, 2006 (http://nm.wu-wien.ac.at/research/publications/b608.pdf)
Concerning the responsiveness of the community: we have in the community no people payed for customer support. There are for every community (and oct) member times with faster or slower response times. But even more important, the responsiveness depends on the types and concreteness of the questions asked.
Concerning bug fixes: the statistics in the bug tracker are somewhat misleading. More entries entered this year were actually fixed than there are still open. Most of the open bugs are from the huge array of optional OpenACS packages. No question, we could do better on that. Since many sites (we included) use OpenACS in mission critical systems since many years, i would be tempted to say that at least the core packages are free of mission critical bugs.
