I never broke them. That's the only good thing I can say.
Where do I start? The crank boss around the spindle dents when grinding ledges goes wrong. They don't slide on unless you use the tool provided. The allen wrench needed is an odd size. Pain in my arse switching from my stem allen wrench to the one I needed for the sprocket boss screw.
Despite all my issues with them. I had them for like 5 years and never broke them. When I sold my bike, they went with it. Now I have some MirraCo cranks and I don't have one issue with them. By the way I weigh 180 pounds so the MirraCo's and the Profile's held up to my weight. If you're jumping from the second floor with these profiles. They'll likely break, but then again why the fuck would you jump off shit? It's not a trick and looks fucking dumb IMO. Get a mountain bike for that Evil Kneivel shit.