I rode nothing but Shimano cranks for 13 years . . . until recently. I went to an FSA Modular Adventure (46/30) crankset and I have been very happy with the results. The gearing is what I want but, to my surprise, the shifting (and lack of noise) is perfect. No real difference (shifting wise) between the FSA and the Shimano cranksets on my other bikes.
To go to the Shimano gravel crank requires not just the purchase of the crank, but also the purchase of a new front derailleur. That makes it an expensive upgrade. And I doubt it will be available as a separate component to the public until 2020. (I hope I'm wrong, but history has a way of repeating itself. Shimano tends to "introduce" things nine months to a year before they are generally available to the public.) As it is, I'm perfectly happy with the FSA. I won't be changing.