While mine hasn't broken, after 20,000 miles we've decided we want our keys back.
I hate the push (or in your case - smash) to start system. Mostly we hate the big fat fob, which has to be carried on your person, usually in my pocket (and not comfortably). I had a 2011 Nissan Murano, which at least had a slot in the dash for the small thin fob. It didn't have to be in there, but it was a convenient spot so you didn't lose track of the g.d. thing. On my Ram I have to stick it somewhere where the truck still can sense it if I don't want it in my pocket on long trips. The wife doesn't know what to do with the fob, as she often carries no purse and has no pockets. Regarding the button itself, I find myself pushing the button repeatedly if I want just the accessory position, or if turning the truck off from accessory. Then there are the times I start the truck instead of turning it off from accessory, because my foot is resting on the brake.
So to sum up: it's easy to lose, inconvenient to use, and more expensive to replace. I hate the system. Give me back my key.