Matt & Trey stated that this is their least favorite episode and they regret making it. Personally I think it's slightly underrated, no it's not a masterpiece but it does have it's moments. I'm quite familiar with the story it's based on and I have actually read the book. Which may be the reason why I appreciate this episode more than regular viewers.
No it's not an accurate representation of the book.. Robot monkeys and 17 year old American guys with cars in 19th century England, I mean c'mon lol. It's not supposed to be accurate, it's a parody and a fine one at that. Far from the best South Park has to offer but not as bad as they say.