His article, which can be read in full here, looked at the pros and cons of rental car cover. He concluded saying: "The take-away here is straightforward. If you can accept secondary coverage, and it covers you fully, your credit card remains the lowest-cost way to protect yourself against big damage claims. But if, for any reason, you want primary coverage, or your credit card doesn't offer complete coverage, third-party collision coverage can protect you against damage claims for far less than the rental car company charges."
Ed noted that rental companies "grossly overcharge for collision coverage. Typically, you pay at least $15 a day, and often up to $30 a day - sometimes even more than the base rental rate. It's a huge profit center." This is a lot more than a policy with Insuremyrentalcar.com!