I replaced my cassette on my Surly Pugsley OP fat tire bike with the sram pg-1030, the replacement to stock cassette that came with this bike. It has great spacing with each cog and I never feel that I can't find a comfortable or appropriate gear to fit my pace. I installed this cassette myself without a problem.
I put this cassette on my cross bike for a wider gear range. I'm using Ultegra Di2 and was using an 11 x 28 cassette. I tried the SRAM 11 x 32 and works great - didn't have to change the chain etc.. Casette is a good value for the price