I have one. Holds bass fine; top or bottom. I generally fill mine from the bottom up, but it is stable enough.
I used to play in a band that had more guitars than Guitar Center. I got sick of navigating through a sea of random guitar stands everywhere.
This thing is awesome. Cost wise, it is slightly more than than the Hercules rack with extra holders, but the GS526B folds down and fits inside my bag along side a pair of speaker stands. Plus fully loaded, the GS526B takes up less space than a traditional folding rack. It takes up the same space as about 2 1/2 single stands.