Last night I picked up a 360 controller after spending a few hours playing Forza 5 and BF 4 on the Xbone...
and it felt weird.
I've been using that controller for 8 years, but I feel like I'm already getting used to the new hotness. The 360's protruding battery pack never (never!) bothered me until now. I've squeezed RT for thousands of BR and DMR shots, but suddenly those old triggers feel tiny and shallow. It's a bittersweet feeling, like running into an old high school girlfriend... and then asking her for the #6 combo (no mayo) and a 5-piece spicy chicken nuggets.
As for the bumpers... here is my totally scientific Truthfact Analysis of the issue:
Figure 1: The Konami Code
On the outside edge of the bumper (Fig. 1, Row 1), it doesn't matter what direction your finger is applying force - the button clicks. My chief contribution to every Battlefield 4 team is mashing the Spot button until orange enemy Doritos litter the screen.
On the inside edge of the bumper (Fig. 1, Row 2), if you apply force directed toward the center of the controller you're pushing against the hinge and the button doesn't click. This happens more if you use the very tip of your index finger instead of the middle. This happens less if you are Davos Seaworth.
The 360 controller didn't have such an issue, but that's partly because those bumpers were much smaller. I think people will get used to the change; in my opinion the Xbox One bumpers are easier to use overall. All other opinions are not my opinion - but they're probably wrong.