I am looking over the webpage now.
PPLNS = ? I assume it only pays per share to the extent of gross revenue?
Not exactly per share. Each time a block is found, you get paid for your hashrate over the last 10 shifts, a shift taking as long as 1/10th an average block. Its comparable to proportional payout, except it cant be hopped profitably, so you dont fork over 20% to hoppers.
However, your revenue is dependent on pool luck. You can have days with no payout at all if no blocks are found, and days where you make 4x as much as you would on a PPS pool.
In the end you should get ~1.5% more than on ABC pool, since there are no fees, but you will have to average that over weeks.