Higher quality bearings than the more common M520 so last longer and slightly less effort :) around £10 more than cheapest M520 but should last a lot longer if you ride often in bad conditions.
Note they require 8mm Hex to fit not the usual spanner.
Very little difference (only finish?) between these and XT/M770 pedals which are around £50 online.
Cleats should be included according to Merlin although not written specifically on this page (important because SH51 cleats cost £9-£17!)
RRP around £70 (!)
Next lowest price around £32 online I think (CRC etc.)
I don't know when the 10% off expires.
(btw HUKD has no Topic (category) for sports equipment?)