I've been to this location (W. Flamingo/Grand Canyon) three times in the past month. Every time, I've had to wait 15 minutes or more for one smoothie. Twice I went into the cafe and once I went through the drive-thru.
When I tried the drive-thru, there were only 3 cars in line. Waited in line for 15 minutes, only to be told (when I got to the window) that they didn't get my order so I had to wait another 5 minutes as they made it.
The last time I went in (on a Sunday afternoon), I waited almost 25 minutes for one smoothie!!! It looked like there was only one person working the register and the same person was making the smoothies. Right before I left, I saw 3 other employees pop up, but who knows what they were doing the whole time.
Won't go to this location ever again.