As Suvat said, both are great firms and you can't go wrong with either, thus your dilemma. At the end of the day, you want to be working in a firm thats a large enough for good professional development and opportunites and also good in terms of personal support and a nice working environment.
Professionally, both firms are excellent, though im kinda biased to PwC in terms of their larger client base.
But in terms of personal support and working enviroment it seems you're more inclined to EY as the culture seems friendlier. I felt that way originally too (though i didnt get into EY) and thought PwC is really tense and they just work u like crazy. But after PwC insight i realised that PwC was a realy nice place and the people were really laid back.
No doubt there would be a corporate ladder and probably tense moments, but i mean, thats what ur hired for right? Your ability to deal with all that and be an effective business leader/team player.
PwC is also quite people focused too cause they realise thats what makes them what they are. I was talking to this manager in Business Assurance at the celebration night and he plays soccer on a competitive level, so he'd require a lot of time to train etc and its fully supported by the firm. Theres a girl who does that too, cept shes in netball professionally, and its also supported by PwC. PwC is quite focused on tailoring to the people's needs cause at the end of the day, thats what makes them the money =).
So overall, there really is nothing to separate the firms, but i personally would go with PwC cause of the larger client base, meaning there would be more clients and also more interesting ones to work with. That's just my biased opinion.