Funny you should mention the 11-42 cassette - it cropped up in a conversation I had today with Chris, the manager of my local bike shop.Popped in to visit one of my mates today at his new cycle shop, and came away with an early Xmas present.
One 11-42 rear cassette, on one dirty bike, from yesterday nights ride.
I had anticipated a new rear mech and longer chain, but the only thing required, was a slightly longer 'B' screw.
He's in the habit of buying a bike or two a year which, at staff discount, he can sell after using them for a few months without losing much money.
It gives him a chance to give new models a proper test so he can better advise customers, and he gets to play with new bikes.
His latest purchase is a Cannondale single speed bought because it can take gears, particularly the new SRAM wide range cassette, so he will run 1X10.
Apparently there is a shortage of Shimano shifters.
Chris prefers 10 to 11 speed because of the stronger chain, and usually, the more widespread availability of 10-speed bits and pieces.