I stayed there late December.
The hostel itself is actually near Akebonobashi station, which is 2 stops on the Toei Shinjuku (green) line from Shinjuku station itself, so I wouldn't call it stumbling distance if you intend to get wasted in Shinjuku bars. Keep in mind that a single trip from shinjuku station to Akebonobashi is 170Yen, and trains stop running quite early (like 1am from memory although I'm not definite on that). I walked from shinjuku to the hostel once, and it took about 20mins, and was an easy walk so maybe you could do that. Taxis are expensive in Tokyo, flagfall is 800yen.
The hostel itself has pretty good facilities. Very, very clean bathrooms (although you have to pay 100yen to use 10min of hot water), washing machines, free internet and free towels. The bunk beds are actually little 'cubby' houses with curtains, so good for privacy. There's a common room upstairs that is a bit hit and miss in terms of fun vibe. Some nights I'd go up there and there'll be noone there, othernights it seems like everyone is there and having a great time. There 's an Asahi vending machine up there as well.