Forum OpenACS Q&A: Re: Colocation for OACS
I don't claim to be typical, but IMNSHO the most important thing is the ability for complete, utter control for the customer via ssh login. Other value-added services can be very useful, but I would never trust a manged hosting anything without the fallback to root access on the (either real or virtual) machine. My take on it is if the hosting provider isn't good enough to be able to give you that safely and productively, why would you trust them to be good enough to make any of their more point and clicky value-added stuff work right?
I haven't used it myself, but Acorn Hosting's setup sounds like the best solution for shared server (low cost) solutions. See the community page. (Acorn uses a Linux kernel patch to achieve essentially the same thing as FreeBSD's jail facility.)
Since I don't think she's doing the hosting for the money, Cathy might be happy to give you advice, what her users have asked her for, etc. There are other folks doing OpenACS hosting that also might be happy to do the same. If you can encourage them to respond here it'd be interesting to hear what they have to say.
As for the value-added features themselves: Webmail sounds very useful, and a lot of people seem to want it. Off hand I can't think of anything else to add to David's list.