Quote from Marion "Sure, combining the flatpicking and fingerpicking would make you look cool - but what advantages does it offer to make up for its disadvantages?"

Well, I can answer from my point of view. I do it because;
1. I can alternate between strumming and fingerpicking..(It's darn near impossible to up-strum with a thumb pick)
2. A linear fiddle tune can be embellished (makes for interesting accompniment)
3. As opposed to a thumbpick, the flatpick can more easily be used in the typical up/down manner of fiddle tunes (and even if you use a thumb pick this way you still sort of have to reinforce it with your index finger---therby leaving yourself one finger short for fingerpicking anyway)
4.The variety of flatpicks and their style makes for a variety of sounds (ways to attack the strings). The sound of a flatpick is NOT the sound of a thumbpick.


The drawbacks are
1. The imbalance between string volume that you mentioned but this is less material on an electric, and can be more or less ovcercome on an acoustic by wearing fingerpicks on the middle and ring fingers. I also find that holding the flatpick necessarily changes the angle of attack for my fingers and I automatically get more nail on the string anyway.
2. The pinky is the weakest finger and it's hard to train if you rely on three finger patterns.
3. It's a bit tricky to learn the hand flexibility (getting the mid and ring fingers to act independantly). The article to which I referred gives excercises to increase this.