This adventure was a fantastic life experience. Overall I was greatly satisfied with the experience (and we haven't yet made it to Machu Picchu!) Some suggestions and observations.
1) Tipping - it would be very helpful to make the tipping expectations known ahead of time. I travel on a budget and did not realize how many tips we would have to give. This is the only part of the adventure that left me a little uncomfortable.
2) First Night - our guide told us it was going to be very cold. It was cold! Perhaps some recommendations on how to survive the first night better for some of us novice trekkers. We froze.
3) I thought I was in great shape going on this. It was challenging physically. I would recommend maybe a physical training program to have clients prepare for the trek.
4) Our guide Americo was incredible. It would be nice to have a way to view individual guide reviews and select your guide.
I will absolutely recommend Salkantay.org to friends!