I stayed in Halo Guesthouse last year (December 2012) and stayed there for 3 nights or so. Best thing I love about it is that the dorm room in the third floor (IIRC) is big, and there's a huge space in the center. First night I stayed there, I went out to dinner with 3 other guests, only because the space really encourages you to talk to each other.
On the second night, we all had a drink in the room, finishing all the soju that a Chinese girl had brought with her. We had so much fun, and one person I'd met there even visited me in the Philippines several times after that.
The rate of $6 per bed per night is also cheap, considering there's free breakfast. The beds are firm, and the room is cleaned every day.
On the minus side, the bathroom needs to be repaired. The tub is broken and it's dangerous to stand there and take a shower when you can easily slip and hurt yourself. Also, the dining area is very small, and you can hardly move when you're eating.
Like the other guesthouses in the area, they close at midnight, so you have to ring the bell when you get in late.
I recommend this for solo travelers because you can easily meet others when you're staying there. There are cheaper dorms in the area ($3) but this one is so much better.