I want to start mining. One of the questions I have is: which pool should I join?
I'll go over the differences you mention and describe their implications to help you make an informed choice. Location
Server location matters for round-trip time of work requests and share submissions. With todays fast internet connections however, the few milliseconds of difference does not make a noticeable difference in mining performance. There may be legal issues with some locations, but I'm not an expert on that.Hashrate
Hashrate matters only for Prop., Score and PPLNS pools. Higher hashrate means more consistent payouts. For PPS, hashrate does not matter since the payout is fixed per share; no matter how high the hashrate is.Reward Type
For me, one of the main differences between pools is trust: how much do you trust other pool members and the pool operators to treat you fairly? The score method for example needs loads of trust (or audits) due to its intransparancy. But for PPS, the 'other members' risk is completely removed. It also depends on the amount of risk you're willing to take. More risk (Prop., Score) generally means less fees, And lower risk (PPS) means higher fees. We've just launched ABCPool which combines all the positive aspects: ABCPool is a PPS site with a low 2% fee, without any risk of other members cheating.Audits
For those pools in which your reward depends on the efforts of others, audits seem like a must-have. This is because without audits, it is impossible to know that the shares per round are reported accurately. For PPS pools, it's always easy to audit the pool yourself: just compare the number of shares reported by your miner to the number of shares you got payed out for.Protocol
LP is a must, otherwise you're throwing away money. But almost every pool has it.Launched
Older pools imply trustworthiness. However, I think that that is not necessary. With most pools (also at ABCPool) it's possible to have balances as small as 0.2 BTC payed out to you, so your risk of not being paid is limited to that amount. The older (bigger?) pools do seem to be under attack more than newer pools.
I would recommend PPS to anyone, and ABCPool in particular. But that's obvious, since..
[Disclaimer: I am one of the operators of ABCPool.co, a Pay-per-Share pool]