I'm about two weeks in, and I love this stuff. I've recently began to train for MMA seriously, so I've been doing 1 1/2 to 4 hours a day of exercise. I feel fine. This stuff is a blessing, especially on sprint days, conditioning days, etc. It helps some during the exercise itself, but the real benefit, for me anyway, is that my muscles feel fresh after only a couple of minutes of rest. Here is my training log. You can see the difference in my workouts quite easily as far as volume and impressions.
http://www.sherdog.net/forums/forumdisplay.php?f=49
As far as appearance, the definition in my shoulders is much more pronounced, chest, legs, and upper back as well. I can't say for sure it was the BA, as I recently added a few new exercises into my regimen that deal with those areas.
The skin thing still creeps me out. It feels kind of like your foot has fallen asleep slightly, but its your whole body. Took some getting used to, but as others have said, I welcome it now.
I've had the most success with splitting it up into one teaspoon before a light exercise session and one tablespoon before an intense session (I usually work out twice a day, and the intense session is sometimes in the morning, sometimes in the evening). I always carb load it with V8 Fusion juice.
So far, I give this stuff an A++