Of course the bracket doesn't compare to anything like RRS or Custom.
Personally, I never had a problem with the smaller ball head but I know from the original round of testing and and sales that there were complaints of slipping, especially with the grid installed.
Edward also made a change to the bracket so that there is a tighter fit in the sliding channel whereas the ebay brackets haven't changed a bit and probably won't.
Remember, the Cheetah Qbox is a deeper box than the ebay boxes and therefore has a bit more weight to support.
If any of these boxes/brackets were to go back to the drawing board for some re-engineering the price would jump dramatically.