Saw Nyein San was the highlight of our entire trip to Myanmar. The amazing, friendly, generous staff run a very clean, comfortable guesthouse, and are very helpful with any travel needs. Our room was clean, insect-free, and had strong A/C - everything you'd want in a Burmese guesthouse.
Also, the staff makes an incredible breakfast that we looked forward to each day in Bagan - definitely try their mohinga and Shan noodles! Delicious fresh fruit and fruit juices, snacks, and other foods too, with market-fresh ingredients. The food we had at Saw Nyein San was the best we had in Myanmar, and we went to many popular restaurants across the country.
The guesthouse also rents electric scooters in very good condition, and the staff showed us how to ride them and also gave us excellent recommendations about where to go in Bagan. The staff also helped us obtain a Burmese SIM card, which came in handy during our trip, and were extremely friendly throughout our stay. Very highly recommended!