dashriprock, i have never used a BGT but has read many reviews on them. pretty all the reviews are very good and i am also leaning towards getting one.
i have a couple of other one that work ok but if i can recover more yellow with the BGT i am going to try it.
I just got one yesterday and tried it out for the first time. Took a bet to learn just how to set it up properly. I wa surprised how much water flow is needed. Seemed to work well though.