In a discussion between Open Meeting and Adobe Connect, both may have their uses, but I think we need to take into consideration what we might use web conferencing tools for. For a staff meeting of more than four people, for instance, where you wanted to share and work on a document, you'd be automatically limited to just one person broadcasting with Open Meeting. As a presentation tool, it might work fine (although it doesn't seem to get as good of reviews as other web-conferencing tools), but for collaboration, it might not be the best option. Additionally, you can use a free version of Adobe Connect for meeting with up to three collaborators or broadcasting to fifteen that wouldn't even require the maintenance efforts and support of CIS.
The .flv recordings that are generated by Adobe Connect are of high-quality and stored by Adobe to be made available to anyone. You can also incorporate these .flv's into other videos you might create for training or information purposes. I don't know how you host/archive recordings in Open Meeting, but if you lost functionality or quality, this wouldn't be a positive either.
I'd be curious as to how much budget is available for the "named organizer" solution on Adobe Connect (as listed on the Confluence page). At $150 per named organizer, if you only gave the organizing license to each full-time faculty as opposed to adjuncts, this seems like a pretty reasonable expenditure. (I don't imagine adjuncts would typically meet in a setting where at least one full-time faculty member wasn't present.) And again, with some help getting set up from CIS, we wouldn't burden them with support requirements, as Adobe Connect is vendor-supported. Maybe I'm off on that point, but I think that would be the case.