I measure success in PVP by how much fun I have had. I I have to log out due to the fifth crash in the hour, that is not fun. If everything the group tries to do is met with more than three times our numbers who won't let us even take a single keep as we are being gate camped, then it is not fun.
I want to feel like I have accomplished something even if it is just temporary. But what makes PVP fun... the great people who are in my guild.