I have never used it my self but have heard a few horror stories here on HT where it did not come out as planned. In most of those cases it was due to it not curing properly. This is normally due to poor mixing.
My advice...don't short cut the mixing. The resin and hardener need to be fully mixed to work.
Ahhh, sound advice. Thank you!
If you are planning on putting resin over flat stones make sure and dip them in the resin before you put them in place. I made a bathroom vanity with sea glass and just poured the resin on top and I have bubbles underneath each piece of glass. Maybe someone else has more information on this but just thought I would share my experience.