12-28 is the perfect cassette IMO. At least for my riding style and terrain (and fitness). For every 1 time I may wish I had an 11t, there's 5 or 6 times I'm glad to have the 16t. Every other cog is the same on these two cassettes. If it's right in that perfect zone of 15-19 where you feel you are missing a gear, then yeah, the 16t will make a difference. If it's above the 17t, it's the same cassette, so anything above that will be the exact same, and you will feel no difference.