I think if i had that much hardware for 500 plus th, I would build a private pool. I think they would be more $$$ to be made.
But I could be wrong thats for sure.
Since this pool is 0% fee, your expected reward would be exactly the same. However, you'd have greater variance mining alone. So no reason to not mine into a pool.
This past year, I found 3 valid and 1 orphan blocks while mining at Eligius. I have received all time payout of 78.90441370 BTC, and am at 97.37% shares rewarded.
Well:
1. You recieved more from Eligius that if you were mining alone. If you had mined alone and found 3 blocks, you'd have 75 BTC. Mining on Eligius, you received 79 BTC.
2. Having 97% shares rewarded puts you around the same average than the average miner around here, as, even with 0% fees, the pool cannot get to 100% PPS due to work lost on orphaned block. You would do no better mining alone, as you would have a slight chance too of seeing your blocks orphaned.