The site was clearly hit by the Panda, that was rolled out in the past days to all search engines for English speaking users. It could very well be a hiccup, a temporary situation. The site is clearly of high quality, not a lot of ads, good advice (from what I have read) and lots of visitor interaction in the form of comments. I cannot really see a reason why Google would rate the site as low quality.

Scrapers would be on the top of my priority list as I cannot find anything wrong with the site itself.

Becky you found cloaking, can you describe that in more detail please?