My friend and I took the Mongolia Discovery Week tour in the last week of September, and had a fantastic time with Mendee, our guide. We were picked up from UB at lunchtime, and reached the campsite in the afternoon, where Bana and Mendee greeted us.
Almost within an hour of arrival we were introduced to our horses that we would be riding during the week. Mendee was a great judge of character, choosing our horses based on our experience and needs - while I was comfortable with a faster horse, my friend was able to choose a calmer and more chill horse. The terrain is certainly adventurous, but you are definitely in safe hands with Mendee, who is not only a skilled rider but a good singer on horseback!
The campsite and services were also impeccable. We stayed in a ger (there is the option of either staying in a ger or a lodge) which was very clean and homely, with a burner in the middle which was kept stocked with firewood. As we went in September, the nights can get chilly, but it's not something that cannot be easily remedied with a pair of fluffy socks and thick pyjamas. Our food was also super tasty - breakfast, lunch, and dinner are included, and meals at the camp are artfully prepared by Bana, who served a different traditional Mongolian dish every meal without fail. Dietary requirements are also catered to, and as someone with an intolerance I was very glad of this. If you do stay in a ger, the bathroom will be separate to the ger, although this is not a big deal as the shower and toilet facilities are kept very clean, and we never had any issues with hot water etc.
The activities of the week were well-coordinated, and Mendee went above and beyond as our guide. He is warm and talkative, is very knowledgeable about anything and everything you ask him about Mongolia, and no trip was ever boring! The national parks are an absolute gem, and the Chingghis Khaan statue complex is super fun - I would absolutely recommend taking about an equivalent of 20USD for the photo and souvenir opportunities in the complex.
This is a fantastic option especially if it is your first time in Mongolia, and if you want to have a mix of culture, adventure, and scenery. We had no criticisms of Mendee, as our entire stay was really well-coordinated by them, and we were looked after superbly. I would recommend, especially for those planning to book this tour in Spring or September, that upon arrival you discuss the itinerary, so that you can arrange which days would be best for the activities, as weather tends to be less consistent during these times (It snowed on our final day, which was a fantastic sight!).
My one recommendation would be to maybe offer towels and also have a hairdryer available, as these are two things often most needed by travelers.