I love this bobbin as I can easily adjust thread length while working without manually rotating the spool as with ordinary bobbins. Also, it fits my hand comfortably. However, there is a significant learning curve in using this bobbin to say nothing of the fact that you need to rewind your threads on Norm's spools which aren't cheap. While threading is no more difficult than a normal bobbin, winding the thread around one of the arms to get the right tension is difficult. Also, when you cut the thread, you need to hold on to the spool so the thread doesn't automaticaly rewind back onto the spool. This also makes storing the bobbins difficult; if you just invert it in some holder, the thread will rewind. On the Nor-vise setup there's a rubber lugs on the thread post so you can secure the thread end and thereby avoid it automatically rewinding. However, storing more than two bobbins at a time on this post is impracticle.
The bottom line is that I just bought 10 more spools on which to wind thread so one can summize that I really like this product. However, it has it's drawbacks that people should understand before buying. Regardless, you'll still use some conventional bobbins for infrequently used threads but for black, olive, brown, etc. the Automatic Bobbin is a better way to go.