I joined Challenge when they still ran "Thumper", but they launched Viper almost straight away. I was able to sample the same casino on both versions, and my experience was that I did better on the old "Thumper" Jacks or Better than in the new Viper. It should still be possible to run the Thumper versions for Viper casinos, although not all the games will be available. Some operators will still offer the old version as a suggestion for those with Viper problems.
Viper was a fantastic leap forward for the proponents of the dubious sport of bonus hunting. No more staying up all night playing $1 Blackjack, just configure, calculate WR/Bet, enter the figure, press Auto and go and do something else! A better use though is for tournaments, and even learning the game by seeing what the autoplay does.