I have used the same Snobunje for 5 YEARS, riding the mountains 40-50 days each season and have NEVER had any issues. My dad has had the same bunje since 2006. Being inexperienced flatlanders, our Snobunje's have gotten a ton of pulls on them. There is a learning curve on timing and extraction types.
If your breaking your Snobunje, I would say you are exceeding the pulling force recommendations on the packaging. Limit the force you put on the sled when pulling a 'stuck' sled out. Using the 4 ideas below will help limit the tension/stress on your snobuje.
1. Never pull up hill
2. Always kick out under your boards, in front of your sled and free the skis from obstructions.
3. Never pull at an angle sharper than 90 degrees.
4. Do not accelerate to 'pull' the sled out. Just ease forward, and use the tension provided from the bunje to drive the other sled out of the 'stuck' position.
I would also agree with earlier posts.... always hook to a-arms, not ski loops and always wear your helmet/goggles.