I came here since it's the closest drug test available. They seemed just ok, it's good that they have a water dispenser in the waiting area. I had an appointment but I still didn't get in right away and had to wait for a few others that checked in on paper before me. I found out later that I should have told them about my appointment ahead of time, but I find that strange. They should have a record of names for those who have appointments so that my bladder can relieve itself when I expected to be in.
So in essence, you don't have to be prepared before going to get your test since they will make you wait long enough anyways and there is water to get you ready. Not sure if that's a good thing. It probably took about 40 minutes in total but the wait time was 75% of it. I was miserably trying to hold it in so the bathroom part took only 10 minutes including paper work and I was out.