I'm currently working on some metrics for calculating how profitable the pool is for the miners. My initial ideas are:

Variables:
Bitcoin Difficulty d
Miner Mining Speed m
Block Reward r

Miner Key Generation Rate k
Vanity Address Bounty b
Vanity Address Complexity (aka "difficulty", but I don't want to confuse the two) c


Expected Block Reward: (m*r)/(d*2^32)
Expected Vanity Reward: (k*b)/c

Compare the two and see which is higher.


However, if I want to present this more neatly in one equation, it would probably be like this:

Ratio: (b*2^32)/c  *  d/r  *  k/m

The right part is constant for a given miner, the left part is constant for a given pattern, and the middle part is just a simple ratio of difficulty and block reward. This equation is for a single address. If the ratio is higher than 1, you ought to mine for addresses, otherwise - mine for blocks.

I think I will call the left part of this equation Lavishness. To determine if mining at the Pool is more profitable than mining, one would all various Lavishnesses and put them in together into the equation. For multiplicative mining - one would take the biggest Lavishness sum of patterns sharing a single public key, and for additive mining - add all the Lavishnesses of all patterns (but also keep in mind different key generation rate for this method).


So what do you think, is this a good metric?