I have been to a lot of live events over the last two years and each one the booing was louder in the stadium than the cheering. But each time I would then watch the event on TV (if it was), then the cheering for some reason came out better.
It also depends on how many female and kid fans are at a particular arena. Cheering increases as those demographics increase. When you get to places like Phili with a near all male crowd, there is almost no cheering.
Overall (world wide audience) the split is at best 70/30 AGAINST Cena. Most of the overseas markets seem to detest the guy and only the western US seems to "overwhelmingly" support him.