I liked this place a lot more 10 years ago.
As it's gotten popular it's gotten kinda not as good BUT the stuff you find there is much much much more diverse.
Example: I used to go there in high school with one friend every other week and we would split the 3 t-shirts for $30 and get punk band t-shirts.
There were so many options that it was almost hard choosing just one or two and waiting for the next trip.
They used to also do prints onto blank shirts and there was a massive (and awesome) collection of options.
Now, not so much.
You can find all sorts of other stuff there including a small record shop, an organic fair-trade weird clothing place called Fairy's pyjamas, there's a bunch of vintagey clothes and a hair dressing place, but the silk screening they only do in wholesale now (big fat thumbs down) and the options for band shirts and tanks kinda blows.
It's also a tad creepy going down to the dark basement on your own, which sounds lame perhaps, but...get over your fear and go, but personally I'd prefer it if they had a time-machine that transported you to that same exact location but 5-10 years ago.
They didn't even have a t-shirt of The Clash whereas 10 years ago there was about 10 different Clash types of shirts.
sniff sniff