I've had a bad experience with Dobinson shocks though it was about 8 years ago.
I bought a matched set of Dobinson springs and shocks for my first GQ. First trip out (Fraser Island) I came back with 3 completely dead shocks. I took them back to where I got them and they happily replaced all 4 shocks without argument. Next trip out (local bush) 2 of the new shocks died completely. I took them back again much to the sellers shock, he admitted defeat and offered me a set of Old Man Emu shocks for just the upgrade cost (about $20 per shock) and I never had another issue.
As I said that was about 8 years ago, if they were still having issues with their shocks word would have got around they wouldn't be selling any.
Tony