If you are talking a knife to truly be used for surviving in the wilderness, straight is the way to go. A straight knife can be field sharpened on a rock or stropped on a scrap of leather or animal hide. Serrated knives are a pain to sharpen even with specialized tools designed specifically for the task.

Now for a knife to keep in your car or boat, where you might expect to be cutting fibrous materials like rope or seatbelts, and field sharpening isn't an issue, serrations might not be a bad choice

Proper tool for the job at hand.