Riding '25 Storm GT in South Florida. No issues with the rear brake. It only squealed for the first 2K miles, but no issues with the pedal travel, no sponginess, zero issues.
Edit - more info: One thing I learned with my Rocket is to step on the rear brake harder than on my other lighter bike. At first, I was applying, perhaps, the rear brake at the same pressure I learned my other bike needed. At first, I was using the same amount on the Rocket and it felt inadequate. Then, as I was getting used to the new heavier bike, I little-by-little started to adapt and press more, then the bike started to brake with just the rear brake enough as a bike should. Getting the rear brake to perform well absolutely changed how the bike handles at low speed maneuvering.
PS: It is possible that Storm versions have metallic compound pads on the rear brake only. These metallic compound pads brake harder but take longer to conform to the disc, no amount of bedding-in helps. On my other bike I upgraded to metallic compound pads long time ago to add brake performance, it took too, 2k miles for them to stop squealing. Thus, I wonder if it is the same compound used for Storm and only the rear pads.