At the risk of getting hit by the sh*t-storm that has developed around a perfectly innocent question, I'd like to give some thoughts on the virtues of bluegrass for jazzers, ESPECIALLY beginning jazz upright bassists. As a jazz upright player for the past 30 years who began on upright in bluegrass and old-time music, I can say that the experience was extremely beneficial to me! All those roots and fifths played on every other beat (often without amplification) helped me develop my hand strength, sound, volume, technique, time, and intonation in a non-stressful, fun atmosphere while still gaining valuable stage experience and earning $$ while doing it! Also, the requirement to play simply while providing an energetic supportive groove with swing (though of a different kind than in jazz!) has stood me in good stead as a jazz player. One downside is that most tunes in these styles are played in sharp keys, so your ability to function in the flat keys that most jazz tunes employ is not developed.
Regarding the intonation issue in the video that has been dissected here ad nauseum, the first time I listened it did not register in my consciousness. On second listening I did notice some issues, however, for me it did not detract at all from the music. I think intonation is a complicated issue with many facets and perspectives to it. I think most classical players would say some of the same things about jazzers' intonation as has been said here about Missy's in this video. In the end, what matters most is how it serves the music being played. As has been mentioned before, we can all find examples of great playing by bass players we all revere such as Paul Chambers, Ron Carter, and Scott Lafaro that exhibits a somewhat "flexible" sense of pitch.
As to whether someone with "unconventional" technique should advertise themselves as a teacher, let the market decide! If there's someone who has something you want and is willing to show you how to do it, you should go for it! I think the market has decided about Missy Raines!
