The lockers are quite small, so it's impossible to lock up & secure all of your belongings if you're traveling with a large backpack or luggage. Yes, this hostel kindly offers a "free breakfast", but you should likely plan on alternate means of breakfasting; the dining hall was perfectly sanitary, but breakfast literally consists of toast, cereal, milk & juice (and that's it, no else).
The location is great, as Clink is within a short walk of both the St. Pancras International station and the Kings Cross underground station. No WiFi in the rooms, but there is very strong WiFi in all of the common areas (including dining hall & bar). The decor is very friendly, welcoming, and unique.