I just ended up canceling a couple reservations with autoslash. I am sure it CAN work, but find that I can always do better. sometimes much better. I think one of the issues is, coupons and discounts. For example, if I go to the hertz site, I can get one rate, get another if I put in my AAA number and get another if I select a hertz AAA promo number, all for the same car, all for the same dates. Autoslash will do similar, but won't really check them all - and they are ALL going to be different and one will be cheapest. Another issue is, prices change. While I THINK autoslash must have some sort of AI engine that goes out and prices things periodically, coming back with an alert for THEM and for ME that "hey, we found the rate went down shall we rebook?" Or sometimes I WILL get the "hey, we found a full size for the same mid-size price, shall we change it for you" what I find is that I personally can go in to a hertz or thrifty, etc., re-check maybe every couple days and lo and behold ONE of those days the rate will have dropped - and I rebook it. Cancel the previous reservation and I am all done. I don't find that this happens too often or at all with Autoslash. I have purposely been booking with them to see if it will rebook and/or offer the lower rates but alas it doesn't or hasn't yet. Please don't misunderstand this post!! I think the service is doing a great service and for many/most it can provide a lower overall cost. I'm just saying that with a little elbow grease and patience an informed traveller can usually do better.