Do not use where a "hold" will likely occur...such as gas stations and restaurants.
I thought this was a great idea...it paid more than my amex rewards...so I exchanged them for a gift card. In the end, it was more trouble than it was worth...and the holds are not discussed in the purchase. There will be a hold on the funds...and if there is any problem with the hold...it holds the amount for several days...and in one case, it took 10 business days for the amount to go back onto the card! It's great for purchasing online...or in a regular store.
Rating: 2 stars