Personally i prefer Ghash because they offer a userfriendly website. I can automatically split the income between several wallets for example.
And most mining pools offer apps to check your hasrate on your phone or on a google chrome plugin. So you don't have to check all the time if your miner is still running.
If those things would be created for P2P to make P2P as userfriendly as Ghash than personally i would love to join P2P. But ight now it's just too much of a hassle.
How about listen to the actual miner who commented here? It sounds like money needs to be spent to making mining for P2Pool the easiest, slickest, smoothest way to go. That would suggest to me that donations would be better spent paying developers to implement the kind of interface that miners want. Something that reduces their headaches. It makes sense that large pools would have the resources to provide this kind of thing whereas P2P being a decentralized open source tool probably still requires the command line to get running. What we need is the Ubuntu (company) for P2Pool.