I haven't seen too many issues responding to fingerprints but I will say high humidity can sometimes slow you down. I haven't found anything that a quick cloth cleaning didn't fix but in sunny (and humid) Florida it doesn't hurt to keep things clean and code a couple extra fingers just in case. Overall, I'm sure the A9 and HTC 10 both have nice quick and responsive readers. I'm curious how things will perform going from season to season.
-Rob
Sprint Product Ambassador
Disclaimer: The Product Ambassadors are Sprint employees from many different parts of the company that love technology. They volunteer to test out all sorts of Sprint devices and offer opinions freely to the Community. Each Product Ambassador shares their own opinions of these devices, therefore the information in this post does not necessarily reflect the opinions of Sprint. The PA's do not represent the company in an official way, and should not be expected to respond to Community members in an official capacity. #sprintemployee.