The trek overall was great. The right level of challenging. They also used the first day to let you acclimate to hiking at altitude and gave a hard uphill hike that made the second day seem less difficult than it might have been otherwise.
It gets very cold at night, so make sure to bring layers, and definitely make sure to bring rain gear and covers for bags. The 5 day - 4 night was fun because it included hot springs but I might have done the 4 day - 3 night instead as the last day before Machu Picchu was only a short hike along train tracks.
All in all very much liked this company!