[quote name='thumperbob 2002' post='1183533' date='Mar 31 2011, 04:47 PM']No notes or tones should be avoided- it will limit you- keep an open mind.
Just my tuppence[/quote]
Precisiely. Why limit yourself? And although the physics may well indentify a differrence between an open string on, say, a bone nut, and a fretted note, if it was a massive difference, there wouldn't BE bone (or anything else) nuts - just metal nuts or zero frets. For certain, no-one listening live or even to a record, is ever going to hear that differrence.
And yes, I use 'em all the time. They do require extra thought for damping, but that becomes as automatic as any other part of your technique.