What is the general opinion of the Autozone house brand of engine oil labeled as full synthetic? Is it as good as some other synthetic oils out there and is it worth the price or are there better options? Looking for an engine oil to use in my sister's 4cyl Chrystler which sees cold starts, short trips, infrequent maintenance (if I don't keep track and do it, she wont). Does not appear to burn or leak a noticeable about of oil, even after switching to Napa brand synthetic last change...