2. PPLNS, Proportional, etc etc... (Ghash.io, Eligius, Kano, Slush, BTC Guild, etc...)
This payment model essentially waits for a block to be mined... then uses some algorithm to distribute the proceeds based on a miner's contribution to the pool. It sounds fine at first however there are some main issues that are unacceptable. This payment model allows the pool to be dishonest. There's nothing stopping a pool from doing a few things.
1) A pool can choose to not report a block mined to the members of the pool. Essentially it'd allow the pool to keep the 25 bitcoins.
2) A pool can 'make up' miners and say they did 'x' amount of work or manipulate stats of either their own miners to give itself a bigger share of the 25 btc.
3) You have to 'trust' that the pool operator(s) are being honest about the statistics.
Simply put, I do not trust the pool operators.
Except that as I have stated about 1) elsewhere before, stealing the blocks is not likely to succeed, most likely to fail and the OP gets caught and you send the police around to charge them with grand larceny.
The cgminer API and log and stats all show when you find a block.
Who doesn't notice when they find a block?!?
So how is a pool going to steal that block without being caught out?
Well they have no guarantee that they wont be caught ... so 1) is not really an option for a well standing pool.
3) is a repeat of 2) so no point responding to it.
2) is of course a possibility but again, either the pool would have to be stealing a very small %, or the LONG TERM stats would show the pool as being untrustworthy.
However, to respond to your last comment, if you do not trust pool operators, then don't mine on pools.
Mine solo. Simple solution.