The right side of my Iron Cobras broke, after ten years plus of faithful service. It might have to do with the fact that I've been practising a fuck ton for the past year to get better at double bass.
The replacement piece is on order but in the meantime I rented some other ones, a mid-level Pearl pedal called 'Demonator'
which is apparently a hybrid of the Demon Drive and Eliminator pedals. Much cheaper.
You know what? I like them a lot. They are much lighter. It's almost like just tapping your feet on the ground. I think now that my problems with double bass for the past ten years may have been the Iron Cobras. This is a rare instance where you actually can blame the gear, and obtain other gear and instantly become better. The Cobras are just too heavy to activate. I am hitting tempos with single strokes on the Demonators that I couldn't before. This is really great.
I never found them difficult, and I'm not a particularly hard hitter. I also play heel-down, if it's anything. A friend of mine had the Axis longboards for quite some time and they were definitely a different feel; I wasn't used to them and found them a bit difficult to control, honestly- very light. I'm also not a very good drummer, though, so that's worth considering.