The Scotland based meta-search engine was purchased last year by the Chinese firm Ctrip. It quotes prices in Great Britain Pounds (which is fine by us Marriott Premier credit card owners) and has significantly beaten my usual go to car rental vendors, Hotwire and Costco by three figures for a weekly rental. It offers the same rental cars as the others (Dollar, Alamo, National etc) at the same locales.
If no experience with cars, I'd take your experience with either their flight or hotel operation as well. It looks fine, I just get nervous anytime I beat the going rate by so much ($215 vs. $375..and yes, I did the currency exchange ). Thanks