We had an amazing experience with Ethos. It is hard to find a tour operator who offers a set of itineraries while maintaining a unique experience, but I think Ethos have cracked it.
We were not sure on what trek to do, but after emailing back and forth with Hoa, she gave us good recommendations and helped nudge us towards a choice.
We did a one day trip to visit the Red Dao, followed by a two day, one night Buffalo Valley trek and would recommend both.
Our guide for the Red Dao trip, May Chan, was so knowledgeable, warm, kind and helpful. She led us to her home, through the countryside and past lots of farms, answering all our many questions.
We had a really tasty lunch and helped with some of the cooking. After lunch she showed us some sewing and (with incredible patience) helped us make some bracelets. We finished the visit with an amazing herbal bath. Definitely worth paying the few dollars extra!
We returned to Ethos the next day to begin our Buffalo Valley trek with our guide Chey (hopefully spelt correctly). She was so chatty and really looked after us. She told us all about the areas we were walking through and the traditions of the Hmong people. She cooked lunch for us with her beautiful family at her home and really welcomed us. The trek takes you through some amazing scenery and we stayed over in a homestay up in the hills with a really nice family with an adorable little baby girl who kept everyone entertained. The food was very tasty, they even cooked french fries for us. We slept in our own house just up hill from where we cooked. The bed was pretty hard but we slept well after all the walking.
It is clear Ethos really cares about its guides, the experience they provide and supporting the different communities. It has been one of the highlights of our trip to Vietnam and the guage to judge our other tour trips.
Even though Sapa town itself was quite busy with tourists (it was a weekend), once out in the villages we didn't see any other tourists, just plenty of water buffalos, rice terraces and cloud shrouded mountains.
If trekking, I'd definitely advise taking a bamboo walking stick from the office, it saved me from tumbling into the rice field more than once.
A great experience.