i would also add that the QoS performances of a well-planned BBH network are usually better than a SFH network.
SFH relies a lot on a regular cell design, in order to provide good QoS. In real networks, it is never so regular (usage of lower/micro layers, presence of high sites, etc…)
BBH relies on human/machine intelligence to plan frequencies where the risk of interference is the lowest, which will always ensure a good QoS.
It is just my opinion of course.