Have to say you were either unlucky or I was very lucky in that instance. Having used Stansted a few times of recent during peak times I have to say the airport experience on arrival was good compared to previous times. I have had bad experiences of Gatwick's arrivals when I last used the place in the Summer.
I'd still rate Gatwick's arrival experience above that of STN. They could still learn a thing or two from London's second airport, but overall STN has improved considerably on the last two occasions I've used it and was pleasantly surprised.