I am about to order my first Macbook ever, and I need to decide between: 13 inch 2.8 i5/512gb SSD/8 GB RAM 15 inch 2.2 i7/256gb SSD/Iris Pro 15 inch 2.5 i7/512gb SSD/Nvidia. (These are my only options, I cannot configure them where I live.) So I decided to go for the top model, but I realized I will need to run Windows at times due to specific company software. How bad the battery life is going to be since the 750m GPU will have to be ON all the time? I would have gone for the base model, but I do not think 256 GB is going to be enough for me, especially with the Windows installation. These are my only choices because I am getting them from a local company and using my company's discount.