I did the canyoning tour in the Río Correntoso, it was great! You will see scenery you have never seen before in your life. When you're down in the dark and craggy canyon, the river rushing around your knees, you'll look up and see a shaft of sunlight spilling through the narrow opening above to illuminate the thick hanging moss that clings to the rocky canyon walls, and you'll see the glimpse of the quiet, sunny world above, and you'll feel like you're on the cusp of two entirely different worlds. Then you emerge into a wider part of the canyon and it's like you've entered the realm of fae. I've tried to describe the feeling but you just have to experience it yourself.
The two guides were very nice, fun, reliable, and even good-looking as well. Despite initially being nervous, I always felt safe with their expertise. Afterwards we went to an idyllic farmhouse in a field straight out of a 1800s pastoral painting and ate snacks with some cats. (Note: some other agencies don't pay the owners of the pasture for this route out of the end of the canyon, so you have to hike all the way back up through where you came.)
Also, you need good hiking shoes! Otherwise you will definitely slip. Also, bring another pair to change into because your shoes will be wet for days.