100% acrylic latex. We use mostly Benjamin Moore, some Sherwin Williams, both are good products. Buy from a dealer where the pros buy, and ask questions if unsure. They will gladly advise on prep, spot priming, etc. I do not recommend brands from the big box stores, as I find they are not of equal quality.
Although SW Duration line is very expensive, it would be a great product to use in this situation. Soffit, facia and trim won't use more than a couple of gallons. It might be a worth while investment for you.