Is it possible to track multiple workers on Eligius, or will all your miners be shown as a single entity?
You can't track individual workers currently, only global hashrate and income per address. I would recommend setting up a client-side monitoring system, for example cgminer can be monitored remotely, I guess it's the same for BFGMiner.
How's the stability?
Pretty good, mining servers are very stable.
The CPPSRB system is the fairest IMO for those who aren't willing to gamble with variance. Of course there are pure PPS pool, but they either have much higher fees (the big one with PPS at 3% fee has a reputation of a fraction of your accepted shares vanishing here and there, and although I have no proof, I have come to that conclusion myself many times, after comparing counters).
With CPPSRB, if the pool is unlucky for a while, you are paid less (like DGM, PPLNS, prop etc.), but it's only a question of how long it will take before your shelved shares are paid in full. If the pool gets lucky several days afterwards, and you either switched to another pool or stopped mining for some reason, your shelved shares are paid anyway. With other systems, they wouldn't.
Eligius is paid only with transaction fees and donations, which is good in the short term I think, I mean at least as long as tx fees are less than 5% of the block reward.
