Does expression ”宁愿...也不...“ belong only to book style or I can use it in simple conversation？
When the context calls for it, use it in conversation, according to a quick survey of 2 friends!

我宁愿坐火车去。
I'd prefer to go by train.
我宁愿买二手货。
I prefer to buy second hand.
我宁愿跟铅管约会。
I'd rather date a lead pipe.