The disadvantage is you don't get immediate satisfactions like in other pools.  But the advantage is your payout may be higher than other pools.  other pools have to calculate based on block not yet solved.

The numbers to look at is your percentage share for the round.  Multply that percent by 5 ethereum coins and you get your payout, once a block is solved.  If you leave the pool, you will still get a percentage though it will decrease in value over time.  Stay in the pool and you maintain or increase your share.  As more miners join, you share may go down, but then the block is solved quicker.  

The variance is the luck of the block being solved in a round.  Last time we solved a block at 30%  But you  could climb all the way up to 100% and still not solve a block, though based on statistics, at 100% a block being solved will come very soon.

Here is a technical article on statics and luck of the pool and variance.
http://organofcorti.blogspot.com/2015/07/faq-bitcoin-mining-and-luck-statistic.html

Based on hash rate up around 3 GHash we should be solving blocks every 3 to 7 days. with a 5 day mean.  Lucky is sooner, unlucky is later.

For my first round of mining effort, I got more shares in 5 days than it would take me 3 weeks in other pools.  I expect my share to decrease with pool size increase but the payout rate still looks better percentage wise.