Just a point I noted: I made a Hertz rental using Cap1 travel portal and paid $60+ using the travel credit. However, I was charged taxes and insurance at the shop which amount to a total of $92. I called Cap1 and the $92 can't be reimbursed with the VX travel credit. If you use the credit on rentals you might end up getting only less than half your rental amount, which is not economical in my opinion.