Another one for Afam Sprockets here, this time coupled with a DID VX2 chain which since fitting last year and having done about 5k and has only needed adjusting twice.
I bought mine from the lovely people at Bike Torque racing who I have used many times (way back before I had the Monster when they were solely GSX-R specialists). Never had a problem with them and they are more than happy to swap sprocket sizes as I did going up a couple of teeth on the rear.
A little more information from DID here:
http://www.didchain.com/PDF/DID_2014usa_final.pdf
Bike Torque Racing here:
http://www.biketorqueracing.co.uk/chains-sprockets