The main benefit of using pay-to-pubkeyhash is that it allows for much shorter addresses (since a RIPEMD160 is much shorter than a pubkey); other than that it takes slightly more time and space than pay-to-pubkey. When mining, you don't need to share the address you're mining to except in the coinbase transaction itself, so there's no reason not to do it the slightly simpler way. (Historically, the reason is that pay-to-pubkey was originally the standard transaction type). The only benefit I can think of to mining to a pay-to-pubkeyhash instead of is the theoretical situation where a serious vulnerability in secp256k1 has been found; receiving via pay-to-pubkeyhash doesn't reveal your pubkey until you're in the act of spending from that address, and allows less opportunity for someone to crack your key. Of course, no one expects that to happen any time soon.
Thanks. That makes sense. So in Bitcoin I found that consistently older blocks are pay-to-pubkey and newer ones are pay-to-pubkeyhash.
In Mazacoin however I find these randomly all over the place.
Is it now generally the state of the world that pool software all use pay-to-pubkeyhash and individual -qt clients all use pay-to-pubkey? (I noticed all my solo-mined Mazacoin blocks are pay-to-pubkey for example).
