After a week of trying out both pools at various hash rates, heres a little review I came up with. Cant post elsewhere so hopefully it helps someone in this section.
My home mining rig goes up to 370MH/sec (on a good day) and I use guiminer/phoenix 1.48/phatk. My other mining rig is doing just over 1500MH/sec at work.
Paid out as promised. Easy to use web interface and stats updated quite quickly. Found blocks regularly. Hash rate reported was pretty close to the hash rate reported in my client, but was still a little under (considering the drop outs). I put this down to the network timeouts, which were a pain. I know some of the larger pools had some attacks so this may be a cause of those drop outs. The more drop outs there were, the more my avg hash rate went down - and there were a *lot* of drop outs at the network level initially, though this improved later on. My stale shares were very low on deepbit, I think ~1.5% IIRC. Deepbit is the biggest pool.
Overall, I found that Eligius EU paid me slightly more that deepbit at all hash rates I used (total BTC reward vs total shares submitted) . Paid out as promised. The connection stability was better than deepbit, but did still have drop outs. My stale share percentage was higher on Eligius (~5%) even with LP. The basic styling to Eligius web interface could be a bit off putting to some, however I personally found them very feature rich in terms of stats and graphing (once you find the right bits). I did find that Eligius computation of my average hash rate wildly fluctuated. For example, sometimes my (home) avg hashrate was as low as 200, whereas it could go as high as 500 (!?) even though my rig wont go past 370. This could be down to those connection problems though.
I noticed Eligius gets 'unlucky' a lot - the amount of invalid blocks seems quite high, and sometimes blocks take 6 to 12 hours to find on EU. Im not sure what causes these runs of bad luck, but they seemed to happen quite a bit.
Ronseal. They both do 'what they say on the tin'. If I had to chose between the two, I would choose Eligius for the higher payout, more stable connectivity and the fact Deepbit is so damn big.
In real life, I dont have to chose between the two. I find neither of the two pools really works for me in the way Id like and they both seem to have their issues. Ill be using different pools in future and will post up more reviews as I do them.