This was an excellent smog check experience, all seven minutes of it ! Seriously, it couldn't have taken much longer than that, from the time I pulled up until I drove away.
Printed out the $17.99 coupon from the website and drove to this Smogbusters location on a Saturday afternoon. This location on Rainbow just south of Flamingo is one of the few locations that stays open until 6pm on Saturdays instead of closing at 2pm.
There was no wait, the tech was friendly and worked quickly - he printed out the certification and said the information would be transmitted to the DMV in about fifteen minutes, to be sure to wait that long for it to go through if I was going to one of the kiosks to renew the registration right away (I wasn't). Gave him $20 in cash and didn't ask for change - it was great to be able to get this done so fast on a weekend and be treated so nicely.
The smog check is good for 90 days and there are signs posted to remind customers to present the coupon BEFORE the check is started (otherwise it's $19.99 + tax).