At this level, the problems I outlined above apply - non-conflicting logs, smooth load transferring across several servers, etc. It's almost all trivial, but if it isn't documented as a standard, then each new admin has to figure it out for themself and each OpenACS install is different. Barry, how did you designate a single machine to run scheduled tasks? Through the kernel parameters via the admin UI?
Another benefit of using basic HA tools even on a single box is that it make it very easy to start scaling up.