450 VS EPMP i'm not sure if that has been laid out yet, but here is a good spot to do it.
EPMP under the hood is extremely tweaked wifi chipset. and holly crap have they tweaked it and made it made lead into gold in my opinion.
epmp increases in latency as you add subs. its stable, and slow increase, but still increases. it gets more through put in a 5ms frame, resulting in its higher latency. the 450 uses a shorter frame, 2.5 MS resulting in lower latency. the MAC is build from the ground up around this and has no loss in performance while runing 2.5 ms frames, the epmp looses about 10% overall throughput.
so 450, 5 to 7 ms latency, is about double to start, but grows. the 450 doesn't change unless it is pushing its frame utilization.
scheduler, the 450 has definable time slots in the uplink downlink ratio so you can optimize your entire schedule based on your network needs. as much as 90% downlink. the epmp has the 3 common to pick from.
the EPMP is limited to 120 subs. the 450 is almost double. (238 VC)
the EPMP has to be marked front or back in a re-use situation. if a 3rd AP is heard, it will interfere with its like marked AP.
450 can hear any number of like channel APs, as long as CIR is in line, you will not have uplink or downlink trouble.
so the 450 allows for even denser AP concentration over the EPMP.
as an example. the 900 mhz band only has three channels to use. at our peak we had about 70 APs active. in three channels... all APS LOS to each other, 6 aps per tower and towers only a few miles apart. more than a dozen APs in each channel able to hear each other. that simply isn't possible with EPMP. you can get good density with EPMP with good channel planning, good antennas, and proper sector tilt. but you'll never get the same density from EPMP as you can with 450.
the 450 has lower modulation state requirements than the EPMP. it also has a few more under the hood tricks to deal with noise.
the 450 can code to qam 256 making it 25% faster IF all CPES are coding in that rate.
the 450 can do QinQ vlaning. the EPMP can pass that data, but can't strip both tags. just the outter most.
the 450 is an older system the epmp and operators can use the 450m to go up to 400 meg now in the same 20 mhz channel space they are using, cambium has announced they are going to push that evelope even further, expecting to reach past 1gig in that AP. assuming they can get separate data streams in a 14 mimo Transmitters at qam 256, you looking at a top speed of 875 Mbps aggregate in a 20mhz channel in the future. and 1.7gb in a 40 mhz channel also future (those tops speeds are my personal speculation. cambiums current official top speed in 400 meg with exccess of 1gb future capacity without saying the channel size needed)
the 450 is completely software definable leaving the sky as the limit. the EPMP isn't as flexible, but still flexible.
the 450 treats each VC as separate end point. voice VC are prioritized by the VC and the data rates are definable to the different VC queues, the EPMP reads QoS at layer 2 in the Ethernet frame, while is can still dependably deliver voice, or video content ahead of regular data, the 450 goes one step further to prioritize in the MAC layer itself.
the 450 supports a much wider range of frequency bands. ALL 5ghz, 3ghz 2.4 and 900 ghz. epmp is 5 and 2 only.
for providers in dense environments, the 450, as a system can be many times faster than even the EPMP. in moderate density, or low desnity situations, the performance perks for the 450 isn't as apparent.
the 450 gui isn't much different than its gui from more than a decade ago. and its simple and wonderful. I wish the EPMP had its gui.
if you point a spectrum analyser at a 450 AP you'll see a cleaner radiation pattern then the EPMP.
for us the epmp has been solid and reliable, but hasn't been in the field as long as the 450 or the PMP 100 series. we've got 10 year old radios still working just fine.
as a wisp, we are mostly epmp now. we've got a lot of the old 100 and 320 series and will be adding 450 900 to our line up. the future speed improvements will be nice on the EPMP but the 450 is arguably the very best wireless edge access platform out there.