Their reservation is not reliable. I was able to make an appointment only at the Chapin office, rather than the closer office in IRMO since it's not operational. In addition, it took me more than 6 hours while their first estimation was 3 hours. I think they just pushed my appointment back for some other orders because it's the discounted Groupon deal. And the quality of the work was awful. They said it's very hard to get rid of some gunks. Hey, this is why I'm hiring a PROFESSOSIONAL rather doing it by myself. They should know how to get rid of the old gunks with high efficiency.