In Tokyo 2 weeks ago I went to 24 in Shinjuku 3 times between about 5 and 10 pm. Always busy, loads of handsome guys, and had little trouble scoring, including with one 24 yo who loves being with much older guys.

One travel suggestion for those new to Tokyo. The guides usually suggest finding 24 by taking the red Marunouchi subway line to Shinjuku Sanchome station and then making a long backtrack. I found a shorter (and I think much easier) option is to go to Shinjuku Gyoemmae station. On the platform with trains coming from Akasaka/going towards Shinjuku, there's an exit at the front of the train. Go up the stairs to the street and you come out at a traffic interestion. Keep going straight ahead, cross the intersection, walk about 50 metres and turn first left. Continue walking about 100 metres to the 2nd road on the right (just after the road you're on has curled slightly right) and you cannot miss the 24 sign. It's on a conrner about 20 metres down on your left side.

Final note - at Shinjuku Gyoemmae station, if you are coming from Shinjuku, mid-way along your platform there's an underpass that gets you to the opposite platform.

This may sound confusing - but it's really very easy!