the difference is michael is that the extreme range is hi modulus carbon fibre making it more rigid and even lighter.i know i didnt think it was possible after the slx and supermax range!
if your only poling a few days a week then i would say stick with the slx/supermax range of poles but when your poling day in/day out with an increasing workload that includes large domestics,commercial and solar panel cleaning on roofs then i think the extreme poles will be a good investment.
time will tell though!
best wishes
dazmond