I appreciate reviews since I use them as a base for my accommodation choices, so here's my rundown of Space Hostel:
Location: There's a lot to do In Tokyo, and it's well connected via the metro. The hostel is located on the northeast side of the city in Ueno, a good 25-30 minute subway ride to the city center (Shibuya, Shinjuku, Roppongi). But there's a subway station located just 3-4 minutes in walking distance from the hostel that can get you anywhere, which was helpful.
Cleanliness: The hostel was very clean, esp for having at least 18 people on each floor, there were no issues with the bathrooms or sinks or the room themselves.
Staff: The staff was great. All of them spoke great English and were very helpful.
Safety: As a solo female traveler, I felt safe with the hostel/location, even late at night.
Overall, this was a good hostel. It has a nice common room area where you can sit, relax, and get to know others. At the end of the day, it's a hostel, not a hotel, and for the price I paid in Tokyo, it was very doable.