I'm a newbie with this equipment, for now I am playing with a pair of Omnitiks.
There's a useful feature I *really* miss: a receiver side attenuator. It can be very useful to battle high noise. It allows you to increase the output power of the transmitter to achieve a higher S/N ratio, while protecting the receiver from overload, intermodulation, etc.
I remember it was present in the atrocious and terribly expensive Alvarion devices I used years ago.