ETOPS of 300 minutes or longer for the GE90-115 will have three effects:
1) It will give Boeing a boost in selling the B777-200LR and B777-300ER against the A330 and especially the A340.
2) Boeing will not be able to sell B747-400s. Anyone who needs them for a narrow niche between the 777s and the A380 will buy them used.
3) It will lower the cost of transpacific travel.