I find Google more and more disappointing when trying to get useful sites returned from a search.
Quite often i'll want to see reviews of a product before I decide to purchase it and i'll type in something like '<product> review'. The first few pages will be around 90% full of shopping portals that are nothing to do with a review of the product, being mostly price comparison sites.
Whilst these are sometimes useful when a decision to purchase a product has been made, I do feel that Google is allowing these sorts of sites to 'spam' the search results.