The situation:
I want to play around with IRC bots as general communications interfaces to other code I am investigating. The server hardware would be old and low-memory, but running on a relatively up-to-date Debian GNU/Linux install. I don't expect more than a hundred users at a time, tops, and probably in the single-digits most of the time. The interfaces are more of interest here than the server itself, so I'd prefer something relatively simple to maintain over something with a huge number of configuration and tuning options more useful to a larger site.
Referencing the Wikipedia comparison and the Google PageRank list against the available package list for Debian comes up with the following top contenders: Undernet (ircd-ircu), Ratbox (ircd-ratbox), and Inspire (inspircd). Unfortunately, I can't find any serious comparisons of them, so I'm hoping that asking here will provide a faster solution than just trying them one at a time until something frustrates me enough to move.