This is a Harris Cyclery exclusive, designed by Sheldon Brown, using Shimano sprockets.
This is intended to provide nice low gears and still preserve reasonably close spacing in the cruising range, without wasting gears by devoting space to ludicrously high gears. This is intended to be a good match for bikes with traditional "full sized" chainrings.
It is generally good practice to replace the chain when you replace the cassette.
Over the last 5 years I cycled over 60.000 miles, visiting 50 countries and carrying everything needed for a long trip including a tent and winterproof sleeping bag (see www.jkoelstra.nl for maps and pictures). On average the cogs are getting worn out after some 7000 miles when not changing the chain or after some 10000 miles when changing chain each 2500 miles.I don't want any other cassette any more (unless it would start with a 15 or even a 16 teeth cog)The pro's: = No highspeed gears that I will never use on my heavy loaded bicycle = Steps between the gears are small all the way up to the lightest mountain gear
Bottom LineYes, I would recommend this to a friend