I can feel a difference. The big ring is much easier to run through on the flats. Jumping from 19 to 17T on a 52T ring takes about twice as much energy it seems than having that middle cog if the road is flat and there is no wind or hills to help. I like it much better. There is no doubt that the shifting is smoother, and the big ring is easier to get going in. The 18T is a cog I wanted. Im sure everyone has their own preference in a gear setup, or maybe even multiple cassettes depending on the ride they are going on. Either way, the proof is in the ride. I ran my typical loop today of 30 miles and noticed the difference and improvements in speed (I could use the big ring more often) as well as enjoyment (love smooth shifting).