We've been using the Big Shots (x2) at the park since before I started there 10 years ago, haven't had a problem yet. We've used them at various pressures up to 120psi without issue (just don't hit anyone with them!)
A tip we've learned over time - if you're using the rolled streamers, you'll want "caps" for them - it seems to make them unroll and "stream" better. (We eventually started making our own caps out of old park handouts, much cheaper than what AIM was selling the actual caps for and can get 6 out of one sheet - trifold then half) However conversely we learned through experimentation that confetti seems to work better without caps. YMMV.