Came at opening at 10 am on a Sunday, because an employee previously recommended to come during opening. The line was about 40-50 people (the little girl behind me counted 49 to be specific). It took over 1.5 h to get into the store and 10-15 minutes to actually order once you get inside. A custom bar is $15, the specialty bars are $7 and the other bars are $4.75. Credit or debit only!
They ran out of some ingredients before we even got inside (within 1.5 h of opening), and I was told by a friend who came the previous day that they stopped doing customized bars altogether by mid-day. You can order as many custom bars as you want, each with 3 toppings. The specialty bars are also constantly changing every week.
All in all, a unique experience, but in my opinion not worth the 2 h wait, especially with their limited stock on ingredients and specialty bars. The ruby bar (the pink one, which I was most excited to see and try) was unfortunately sold out.
Note that you don't actually get to see them make your bar, you order and pick up in about 2 h.