In general, I like a plain blade.

In my opinion, serrated blades really only do one thing well, and that is cut rope or webbing. That makes them good for something like a rescue knife attached to a life jacket for rafting, kayaking, or boating. In that situation, by far the most likely use of the knife is to quickly cut free from entanglements in rope, web, fishing line, etc. When you are at risk for being pulled underwater, the small advantage of a serrated blade for cutting cordage is worth it. The only serrated blades I own are attached to PFDs.

For general use, a plain edge is by far more versatile, IMHO. If properly sharpened, it will cut rope/webbing almost as easily as a serrated blade. And a plain edge is vastly better for virtually everything else one might do with a knife.

That's my opinion. Others may differ.