I WILL NEVER USED THEM AGAIN!!!
We booked a holiday through Groupon for our anniversary only to find out at the check in that the company Groupon used to make payments came up as "Fraudulent" and we were refused to board the plane! Groupon then refused to compensate use for their error and even accept any responsibility - it took use almost a month to get our money back. I WILL NEVER USE THEM AGAIN!!