Stayed here whilst traveling solo. Was able to check in at midnight since my flight arrived late at night, as well as check out at 3am for an early flight, even though the reception is not 24 hours there is a bell you can ring so they will come and let you in as some of them live on site.
Overall I would have to say that this is a fantastic choice if you want to be close to Khao San Road (about 5 minute walk) but not so close that it's noisy at night. The rate is probably a little more expensive than most of the other hostels you would find in Bangkok but I think it's worth it - you get the privacy of your own little pod but are still able to meet and talk to others.
I was surprised when some reviewers said they got really hot at night because of the pods - basically you slide your pod door according to how much air/privacy you want when you are sleeping...but I found the air conditioning so powerful that I was freezing and had to slide the door all the way shut! They have 2 massive air conditioners just to cool down the whole room, so it is very cold inside - which is nice after a day outside in the humidity. Feeling stuffy and warm in my pod definitely wasn't an issue for me.
And the best thing about the pods - during the day just lift your backpack into your pod, slide the door shut and lock it - very secure. The pods come in 2 rows, so it's probably easier if you had a pod on the bottom row rather than the top row (where you have to climb a short ladder of about 4 steps to get in)
Bathrooms and showers always kept clean. No complaints here.
Good fast wifi as well as a couple of laptops you can use in the lobby.
The only thing about this place I didn't like was that in the morning, down in the lobby (where you eat breakfast) I seemed to have been bitten many times by mosquitoes, so there must've been an opening there somewhere. The rooms were fine though.
Definitely a place I would recommend for solo travelers who would like to be close to Khao San road, looking for a safe, clean place to sleep.