Great experience, bloody hard work not recommended for fat people, met awesome people, good food, good company, cheeky tour guide, only negative are the toilets and the process of shitting.
would recommend porter to carry luggage and good pair of shoes. The high altitude would be a bit hard for people just arriving to Peru and so hike should be booked a few days after arriving in Peru to adjust to the altitude.
If you white bring plenty of sunscreen and a hat, and insect repelent. If your not very good at spanish not need to worry tour guides speak English and love being calles mamá sita or a papa sita.