So I am trying to figure out this for myself. I have been with Slush's pool for a while, not mining frequently, because my GPU only does like 5Mh/s. But, since they changed it so later shares are worth more, I make almost nothing. Been looking at deepbit, but trying to find the best match for me. What is meant by orphans? Hashes you get after the block is already found?
I'm also trying to figure it out....but so far, I found out that an orphan is:
Blocks in shorter chains (or invalid chains) are called "orphan blocks", and while they are stored, they are not used for anything. When a block becomes an orphan block, all of its valid transactions are re-added to the pool of queued transactions and will be included in another block. The 50 BTC reward for the orphan block will be lost, which is why a network-enforced 100-block maturation time for generations exists.
https://en.bitcoin.it/wiki/Block_chain
Here you can see the % of all pools:
https://bitcointalksearch.org/topic/btc-mining-pools-list-104664
and the Top Ten: https://bitcointalksearch.org/topic/current-top-10-pools-current-pps-rates-updated-11232012-106417
Top Ten Pools
1.Deepbit 3927 GH/s
2.50BTC 3651 GH/s
3.BTC Guild 2651 GH/s
4.Slush's 1973 GH/s
5.EclipseMC 1889 GH/s
6.BitMinter 1229 GH/s
7.MT. Red 876 GH/s
8.OZCoin 840 GH/s
9.P2Pool 372 GH/s
10.LTZod 367 GH/s
Courtesy of organofcorti weekly pool watch Updated 10/01/2012
Current Difficulty 10/03/2012 3054627.52695
All Information Can be found on http://www.btcmu.info/
Neighborhood Pool Watch http://organofcorti.blogspot.com/