Welcome to the forums!
You will find that most people here are plain edgers. If you cut cardboard, rope, and other fibrous materials all day long, serrations shine. But, for many of the other every day tasks we do, a plain edge with a coarser grit sharpen on them will do better.
As for self defense, well, I'm not sure if there is any consensus here. Chris Caracci (who has a forum here) advocates partial serrations. I don't like serrations, as from my limited testing the serrations have grabbed clothing. If you got to the Practical Tactical and Chris Caracchi forums here, and do a search (hit the search button and sellect the tactics and training forums), you'll find lots of posts to read there.
Good luck!
By the way, my first quality folder was a combo edge, but now I won't buy combos at all.