I love the Labyrinth so much!
I've been going here for the past 4 or 5 years whenever I needed to restock on my manga collection. Although there is usually (almost always) one staff chillin' by the cashier, I don't see the problem with it as my questions always gets answered and whichever is the staff for the day is always nice. The place is usually empty albeit one or two customers on regular days, anyways.
They have a rewards program that's buy 10 (with every purchase you do) manga (I don't know if it applies to other material) and get the 11 for free. Although it might not seem much, it actually helps in the long run since I tend to buy my manga in bulks.
They also have a blog site for updates on new stock of merchandise, illustration books, manga, comics and even just relevant news on the anime/comic world so that's also a plus.
The Labyrinth is awesome and it's always on my to-go list whenever I go downtown whether I need to buy something or not. Definitely give this place a try for your bookshelf needs if you haven't already. (: