Just gotten back from the Salkantay trek (4 days). It was a great adventure made all the better by the great guide, the awesome cooks and horsemen and finally the other trekkers !
Rami, our tour guide, did a great job at making us feel safe. He was always on hand with coca leaves and "magic water" to help with the altitude sickness ! He was attentive and organized always making sure that we got to where we needed to be in good time.
Downsides were that the high altitude camping on the first night was very cold (didn't get much sleep), and also for some reason we only got a one way bus ticket up to Machu Picchu on the final day rather than a return. All round, a great trip, thanks !