I stayed at Nestay Ryogoku and enjoyed it a lot.
The appartment at floor level is brand new and perfectly clean. Overall surface is limited but well used and kitchen is separated from bedroom. Bedroom is tiny but place is enough for large suitcase aside to table and a comfortable large size bed. There are plenty of equipments for washing, eating, cooking. Bathroom has a tube, and a washing machine. Environment is secure, rather quiet and 3 min walking from a large supermarket, and 5 min from subway station. Access is perfectly explained with images, and codes to retrieve keys is practical. Furthermore helpdesk is available and well fluent in english.
Given the very moderate price of this stay I consider that the quality for price is one of the best I had in Tokyo so far.
I highly recommend this host for Tokyo visitors