Most hardware for WISPs have back haul throughput rates advertised at 100-400 mbs, yet most end points at the customer premise will see data rates of 6 - 20mbs. Including the bad jitter, packet loss, and burstyness, and you've got something that is only good for browsing facebook.
All the hardware I am aware of still uses the old RTS/CTS methods for media access borrowed from the wifi protocol. Which works fine for 100 end points all within 100ft of each other... But stick 100 end points in a 5 miles radius all trying to get a "clear to send" ack and your in a world of hurt.
Yes I know... some tuning will go along way, but at least with the Motorola canopy family, they defaulted to supporting a 15 mile (or was it 20?) radius. And with the WISP's network admin (which is normally always the CEO's young nephew) never changing the defaults because it "just works". This puts a ton of latency on the network since everything is assuming to be waiting on hearing from the node 15 miles away (that may or may not be there). There are some newer systems out now that use TDMA for media access, but from the reviews I see, still getting more than 20mbs to a CPE is unlikely.
You best bet would be a gigabit back haul with some p2p access points covering no more than a mile or 2 each, but that means many more antennas and no place to put them. I've seen many WISPs "cover" 100+ square miles with just two access points. It just doesn't work.