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.