UPDATE - READ THE OTHER REVIEWS! After writing mine below, I read the other reviews and it looks like we dodged a bullet! Biggest concern...if you are supposed to call the company if your bus doesn't show (at 6:30 am...on vacation) and I waited over an hour on hold today...yeah, well. Glad we aren't going.
Wanted to do the all day Grand Canyon tour but...horrible customer service before I could even make our reservation. After being disconnected once and a total hour wait to make a reservation, the operator was incredibly rude when I said I had purchased through Groupon. She told me I had to print my vouchers (uh, no...I want them on my phone) and call back. When I said that I already had all the information in front of me, she told me to hold and hung up. Took some doing to get the refund from Groupon...but why would I spend my money and 15 hours with a company that has nasty phone operators? I would have called to complain, but you can't get through, and I would have emailed, but the offer no other contact info. So...yelp.