The only time the 18 robs power is in first from a stop. Otherwise, I just adjusted when I shift. I don't downshift a lot because I don't always go into 5th. Pretty simple. Lots of times I find myself cruising along at 70 in 4th. Great for passing
I think it comes down to this, if you do a ton of stop n go and ride two up and not much long distance, 16 or 17 is it. If you ride solo a lot, and aren't the type to always get into 5th, then the 18 is cool. It depends as much on shifting style as it does riding style.