PC. It has a bigger fanbase than Xb one's and it will come out much earlier than PS4.
I honestly don't know about a head to head between PS4 and Xb one. I suspect millions of people who would buy RoTR will have forgotten about it by the time it comes to PS4. And I don't see anyone investing large amounts into marketing a year old game. Not everyone who buys a game is a fan of the franchise. Some people just buy a game because it sounds interesting or they want to give it a go to see what all the fuss is about. All those types of people who have a PS4 but no other platform capable of playing RoTR will probably let this game pass by without giving it much consideration. So my opinion is that the sales potential of RoTR on PS4 is about 50% what it would be if it was releasing this year alongside the Xb one version. And it's hard to say whether that sort of sales potential decrease equates to more or less sales compared to Xb one.
“The fundamental cause of the trouble is that in the modern world the stupid are cocksure while the intelligent are full of doubt.” - Bertrand Russell
"When the power of love overcomes the love of power, the world will know peace."
Jimi Hendrix
